DESCRIPTIVE STATISTICS;

TASK 1: CREATE A FOLDER FOR

YOUR SPSS DATA

and

ACCESS SPSS

Step 1: Log-in using your UoP log-in

Step 2: On ‘My Computer’, find your Student Drive and create a new folder on your student

drive named:

Researching Crim 2 Computer Practicals

Minimize this window

Step 3: Open IBM Statistics SPSS Version 21

Minimize this window

Step 4:

On the Student desktop, there is an applet: MyApps (Application Jukebox).

ail

MyApps

Click on this to find IBM Statistics SPSS Version 21 (or later versions of v.21); and click

Launch.

Alternatively, if this icon does not appear, in the Start Menu, find

ALL PROGRAMS > IBM SPSS STATISTICS > IBM SPSS > STATISTICS 21

Note: Launching SPSS can take up to 10 minutes in any of the pooled IT labs or IT suites if

this is the first time that you are using a computer in that facility.

TASK 1: CREATE A FOLDER FOR

YOUR SPSS DATA

and

ACCESS SPSS

Step 1: Log-in using your UoP log-in

Step 2: On ‘My Computer’, find your Student Drive and create a new folder on your student

drive named:

Researching Crim 2 Computer Practicals

Minimize this window

Step 3: Open IBM Statistics SPSS Version 21

Minimize this window

Step 4:

On the Student desktop, there is an applet: MyApps (Application Jukebox).

Click on this to find IBM Statistics SPSS Version 21 (or later versions of v.21); and click

Launch.

Alternatively, if this icon does not appear, in the Start Menu, find

ALL PROGRAMS > IBM SPSS STATISTICS > IBM SPSS > STATISTICS 21

Note: Launching SPSS can take up to 10 minutes in any of the pooled IT labs or IT suites if

this is the first time that you are using a computer in that facility.

1

Step 5: Close the window: ‘What would you like to do?’

[Click on ? top right-hand side of this window.]

Step 6: Minimize SPSS window

TASK 2: ACCESS SPSS SURVEY 2014

VARIABLES SPREADSHEET

2.1. Log-in to Moodle

2.2. Open the site for Researching Criminology 2

2.3. Locate the section: Resources for Group Research Project

2.4. Locate the Moodle ‘folder’:

SPSS Data Files & Qualitative Data Files (Interview Transcripts)

2.5. In that folder, find and click on the folder: Survey 2014

2.6. In this folder, find and click on the file: SPSS Survey 2014 Variables.sav

2.7. The file should open in SPSS

2.8. Save this SPSS file in the Student Drive folder that you created as part of Task 1.

Name this file: Week 6 SPSS [YOUR NAME].sav

2.9. Minimize the Moodle window.

2.10. In Variable View, have a look at how each question from the survey has been coded

and entered into the SPSS spreadsheet.

Take some time to familiarize yourself with the Labels and Values for each variable.

2

TASK 3: ENTERING THE DATA

3.1. Now open the Data View by clicking on the bottom tab: Data View

3.2. Enter the data from each of your completed questionnaires.

Use the Coding Frame to help you enter the correct values.

Note: Any missing values should be left blank (empty)

3.3. SAVE YOUR WORK after entering each questionnaire

Note: After each Save, an Output file will appear.

You do not save these Output files.

TASK 4: CHECKING YOUR DATA

4.1.Find a partner

4.2.Have your partner check the data entry for two of your questionnaires.

SAVE: YOUR DATA FILE

Ensure that you have used the file name:

Week 6 SPSS [YOUR NAME].sav

Note: We recommend that you save your data file on your student drive. But you can also

save it to a USB.

TASK 5: SUBMIT YOUR DATA FILE

5.1. Email your data file (as an attachment) to your seminar tutor.

Send yourself a copy of this email as added insurance that you have a copy of this data

file.

Note: If you do not complete your data entry during this practical, you must complete it and

send it to your seminar tutor before the seminar in Week 7. You can use any of the Open

Access IT suites to access SPSS.

3

TASK 6: EXPLORING DESCRIPTIVE

STATISTICS

Accessing the Teaching Data Set

(Survey 2013)

6.1. Open the Moodle site for Researching Criminology 2

6.2. Locate the Moodle ‘folder’:

SPSS Data Files & Qualitative Data Files (Interview Transcripts)

6.3. In that folder, find and click on the folder: Teaching Data Set for Computer Practical #1

6.4. In this folder, find and click on the file: Teaching Data Set (Survey 2013)

6.5. The file should open in SPSS

6.6. Save this SPSS file in the Student Drive folder that you created as part of Task 1.

Name this file: Teaching Data Set [YOUR NAME].sav

6.7. Log-out of Moodle and close the Moodle window. (Keeping this window open can

slow down your computer and/or cause your computer to close down SPSS.)

TASK 7: EXPLORING DESCRIPTIVE

STATISTICS

FREQUENCIES:

Sample characteristics

Demographics

We can use descriptive statistics to help us understand large amounts of data.

If you have Scale data, it makes sense to calculate the Mean (the average score) for

variables.

If you have Nominal data, calculating the Mean score would make no sense. For example,

you cannot have a Mean (average) of Male and Female. With Nominal data, we therefore

generate Frequencies.

We will now explore how to generate Frequencies in SPSS using the data that was gathered

from the survey that ICJS students conducted in September 2013.

Note: This data set is only for teaching purposes. You do not include any of the data from

Task 7 in your final research report (Artefact 2).

4

7.1. Exploring sample characteristics (nominal data – frequencies)

Gender, Level of Study, Full-time/Part-time (FTPT)

In Data View, in the top Tool Bar, click on:

Analyze -> Descriptive Statistics -> Frequencies

Move each of the sample characteristics (see above) into the Variables box.

Click on: OK.

An Output window will appear with tables for each of the variables.

Question 7.1.

What do these descriptive statistics (frequency tables) tell us about our sample of

respondents?

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

Minimize the Output window.

7.2. Generating graphs for sample characteristics (nominal data – frequencies)

Bar graph: Level of Study

[Still in Data View]

In the top Tool Bar, click on: Analyze -> Descriptive Statistics -> Frequencies

Move each of the sample characteristics out of the Variables box except for

Level of Study.

Click on: Charts

Click on: Bar Charts and radio button: Frequencies

Click on: Continue. Click on: OK.

A bar chart will appear in the Output window.

Question 7.2.

Is this a clearer way of presenting the results for the year (level) of study are respondents are

in than using a table? …………………………………………………………………………

Minimize the Output window.

7.3. Generating graphs for sample characteristics (scale data – mean)

Pie chart: Age of participant

[Still in Data View]

In the top Tool Bar, click on: Analyze -> Descriptive Statistics -> Frequencies

Move Year of Study out of the Variables box. Or click: Reset.

Move Age of participant into the Variables box.

Click on: Charts

Click on: Pie Charts and the radio button: Percentages

Click on: Continue. Click on: OK.

A pie chart will appear in the Output window.

Question 7.3.

Are there any disadvantages to presenting results in a pie chart?

…………………………………………………………………………………………………..

5

7.4. Editing a pie chart

You can add the percentage values to your pie chart.

[In Output View]

Double-click on your pie chart.

Chart Editor dialogue box will appear.

Click on: Elements.

Click on: Show Data Labels.

Properties dialogue box will appear. Close this box.

The percentage values should now show on your pie chart.

If you want to, you can have some fun playing around with the Chart Editor to change

other elements in the appearance of your pie chart.

Close the Chart Editor when you have completed all the changes you want to make.

SAVE THIS OUTPUT FILE as:

Teaching Data Set Output Week 6

in your folder:

Researching Crim 2 Computer practicals.

End this computer practical

Close the Output File

In the top Tool Bar, click on: Analyze -> Descriptive Statistics -> Frequencies

In the Dialogue box, click Reset.

Close SPSS Statistics

Log out.

6

RESEARCHING CRIMINOLOGY 2

WORKBOOK FOR WEEK 7

2014

(Computer Practical 2)

DESCRIPTIVE STATISTICS AND INFERENTIAL

STATISICS

(SEMINAR GROUP DATA FILE)

Step 1: Log-in using your UoP log-in

Step 2: Open SPSS

Step 3: Minimize SPSS window

TASK 1: ACCESS YOUR SEMINAR

GROUP SPSS DATA FILE

1.1. Log-in to Moodle

1.2. Open the site for Researching Criminology 2

1.3. Locate the section: Resources for Group Research Project

1.4. Locate the folder: SPSS Data Files & Qualitative Data Files (Interview Transcripts)

1.5. Open the folder and find the SPSS data file for your seminar group

1.6. Open this data file

1.7. The file should open in SPSS

1.8. Save the file in SPSS in the folder on your Student Drive that you created in the

Computer Practical 1. Keep the file name the same.

1.9. Log out of Moodle

1

TASK 2: EXPLORING DESCRIPTIVE STATISTICS

FREQUENCIES:

SAMPLE CHARACTERISTICS

In today’s computer practical, we will begin by exploring some of the characteristics of your

sample of respondents, using descriptive statistics.

2.1. Exploring sample characteristics (nominal data – frequencies)

Gender

Level of Study

Full-time/Part-time (Qu6FTPT)

In the top Tool Bar, click on: Analyze -> Descriptive Statistics -> Frequencies

Move each of the sample characteristics (see above) into the Variables box.

Click on: OK.

An Output window will appear with tables for each of the variables.

Question 2.1.

What do these descriptive statistics tell us about our sample of respondents?

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

2.2. Generating graphs for sample characteristics (nominal data – frequencies)

Bar graph: Level of Study

[Still in Output View]

In the top Tool Bar, click on: Analyze -> Descriptive Statistics -> Frequencies

Move each of the sample characteristics out of the Variables box except for

Year of Study.

Click on: Charts

Click on: Bar Charts and radio button: Frequencies

Click on: Continue. Click on: OK.

A bar chart will appear in the Output window.

2.3. Generating graphs for sample characteristics (nominal data – frequencies)

[Still in Output View]

Using the same steps as you used in Computer Practical 1, generate a Pie Chart for any

one of the three sample characteristics (see 2.1).

Question 2.2

Would you use this chart in a research report? Provide reasons for your answer.

…………………………………………………………………………………………………

…………………………………………………………………………………………………

2

SAVE THIS OUTPUT FILE as:

[Name of seminar group] Output file

in your folder

Researching Crim 2 Computer Practicals

NOW SAVE THIS OUTPUT FILE IN MS WORD

Saving your Output files in MS Word means that you can use these files for Artefact 2 and you

do not have to have SPSS installed on your computer.

Click on: File > Export

In ‘Objects to Export’, click on: All

Select the Researching Crim 2 Computer Practicals folder on your Student Drive.

(You may have to use the Browse function to find this drive.)

Give the Output file the same name as its SPSS version: [Name of seminar group] Output file.

Click: OK

Check that:

– the contents of this MS Word file match the contents of the SPSS Output file; and

– the location of this MS Word file is correct

2.4. Close the Output file.

In the top Tool Bar, click on: Analyze -> Descriptive Statistics -> Frequencies

Reset to remove any variables remaining in this dialog box.

Remember: Always reset all variables before moving on to analyse the next variable/ set of

variables.

3

TASK 3: EXPLORING DESCRIPTIVE

STATISTICS

PERCEPTIONS OF ASB

3.1. Exploring perceptions of ASB:

Question 7: Variables 7A – 7T (Behaviours considered to be ASB)

In the top Tool Bar, click on: Analyze -> Descriptive Statistics -> Frequencies

Move each of the sample characteristics (Variables 7A – 7T) into the Variables box.

Click on: Statistics. Select: Mean

Click on: Continue

Click on: OK.

An Output window will appear with tables for each of the variables.

Question 3

What do these tables tell us about the behaviours that our respondents perceive to be ASB?

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

SAVE YOUR OUTPUT FILES IN SPSS AND IN MS

WORD

3.2. Close the Output file.

In the top Tool Bar, click on: Analyze -> Descriptive Statistics -> Frequencies

Reset to remove any variables remaining in this dialog box.

Remember: Always reset all variables before moving on to analyse the next variable/ set of

variables.

4

TASK 4:

GENDER DIFFERENCES IN

PERCEPTIONS OF ASB

Independent-samples t-test

?

We are going to use an Independent-samples t-test to compare whether there is any

significant difference between female and male respondents in terms of the extent to

which they consider certain behaviours to be Anti-Social Behaviour.

?

The independent-samples t-test is a parametric test that compares means for two

groups of cases, where the data collected on the groups is SCALE (or continuous

data). It enables us to evaluate whether there are any statistically significant

differences between groups of cases. We are going to group cases by the

characteristic:

– Gender (male/female)

Aim : To establish whether there are any statistically significant differences between the

men and women in our survey with regard to the extent to which they consider types

of behaviour to be ASB (Question 7).

For this seminar, we will look only at three of the behaviours:

7B: Vandalism

7N: Intimidating behaviour towards others

7P: Verbal abuse

?

In the Tool Bar: click on Analyse > Compare Means > Independent-Samples T test

Move each of the behaviours (see above) into the Variables box.

Select Gender as your Grouping variable.

Click on ‘Define groups’ and enter 1 as a value for ‘Group 1’ and 2 as a value for

‘Group 2’.

Click on: Continue.Then click on ‘OK’.

?

The results of the t-test analysis will now appear in the Output window.

?

Identify which of the three behaviours have p values that are: p<.05 or p=.05

Question 4

What are the implication of these results?

………………………………………………………………………………………………

………………………………………………………………………………………………

……………………………………………………………………………………………….

Note

If you do not remember how to analyze an independent-samples t-test, use the guidance on

the following pages

?

?

Remember: SAVE your OUTPUT file in SPSS and in MS Word

Remember: Reset the variables

5

Guidance on interpreting an independent-samples t-test.

Here is an example of an Output for an independent-samples t-test.

The first table shows the statistics for the two groups including the means and the standard

deviations.

In this example, it is possible to see that the mean score for females was 2.38 compared with

2.05 for males – a higher score indicates more worry – so these mean scores suggest that

females were more worried than males about being physically attacked by strangers.

However we are more interested in whether this difference is statistically significant (i.e. that

it did not occur by chance).

The second table shows the t- test statistics which you now have to interpret to establish

statistical significance.

Interpreting the t-test is in two parts:

(1) Levene’s test for Equality of Variance tests the assumption that the two

populations being compared are of equal variance.

If this value (Sig.) is more than .05, then you refer to the ‘Equal variances

assumed’ row.

If the value (Sig.) is less than .05, then you refer to the ‘Equal variances not

assumed’ row. In the above example, the Sig. value is .000 and we therefore would

use the results for the row: Equal variances not assumed.

(2) The t-test:

In the above example, find: the t value (t) , the degrees of freedom (df), and the Sig.

(2-tailed) for the row: Equal variances not assumed.

The Sig. (2-tailed) value is the p value.

You will see that the Sig. (2-tailed) value is .000. We would report this as p <.001.

[See Note 1 on following page.)

6

If a p value is equal to or less than .05 (p=.05), we can say that there is a

statistically significant difference between the means and therefore there is a

significant difference between males and females regarding fear of being attacked.

However, if a p value is more than .05, there is no significant difference.

In our example, as p <.001, we can therefore conclude that females were

significantly more worried about being physically attacked by strangers.

[See Note 2 below for the APA format for reporting the results of an independentsamples t-test.]

Note 1:

When you report probability values from SPSS that are displayed as .000, you actually report

is as p < .001.

Note 2: How to report a t-test

T-tests are reported as follows

t (degrees of freedom) = the t statistic value (rounded to two decimal places), probability

value and for each group (mean score, standard deviation).

For example):

There was a significant effect for gender, t (54) = 5.43, p < .01, with men (M 3.6, SD 1.2)

receiving higher scores than women (M 2.1, SD 1.01).

Important: This is a fictitious example. It is not the result for the independent-samples t-test

for our Researching Criminology 2 survey (or the result for our example on the previous

page).

7

TASK 5:

ASSOCIATION BETWEEN

GENDER

and

THOSE ACCUSED OF ASB/NOT ACCUSED OF ASB

?2 (Chi-square test)

?

?2 or the Chi-square test for independence (abbreviated to: Chi-square test) is a

non-parametric test that is used when you want to explore the relationship

between two NOMINAL (or categorical) variables. Each of these variables can

have two or more categories. The test compares the frequencies or proportions of

cases that occur in each of these categories, with the values that would be expected if

there was no association between the two variables being measured. The test is based

on a table known as a crosstabulation.

?

In essence, a Chi-square test determines whether the observed values are significantly

different from those expected. The expected values are determined by assuming that

the phenomena in question are distributed equally.

Aim : To establish whether there are any statistically significant association between: those

respondents who have been accused of ASB and those respondents who have not

been accused of ASB, in terms of gender.

We are going to use a 2 x 2 table:

– Gender (Qu1)

by

– Ever accused of ASB? (Qu32A)

?

Click on: Analyze > Descriptive Statistics > Crosstabs

Move Gender (Qu1) into the Rows box.

Move EverAccussed (Qu32A) into the Columns box

Click on: Cells

In Cells Display window, under Counts select Observed and Expected.

Still in Cells Display: – under Percentages, select Column

– under Residuals, select Unstandardized and Adjusted

Standardized.

Click on: Continue.

Click on: Statistics

In the Crosstabs: Statistics window, click on Chi-square

Click on: Continue

Click on OK

Three tables will appear in the output window:

1) The first table show the details of your data, such as missing data, and total numbers of

items.

2) The second table shows the profile of your data in terms of your chosen variables. Each

cell contains the actual number of cases falling within that category. The cells also contain

8

the expected count – that is the number of cases that we would expect to find in that cell if

there was no association between the variables.

3) The third table shows the Chi-squared value (Pearson Chi-Square). You should note the

Chi-squared value (Value) and the significance value (Asymp.Sig).

Below is an example of an Output for a Chi-square test for independence.

[Important: This is not the result for Chi-square for our survey respondents.]

Note: For a 2 by 2 table the expected count should not be less than 5. If it is less than 5,

then Chi-squared should not be used – this means you sample is not large enough to conduct

this type of analysis.

Step 1:Have a look at the Count and Expected counts in the 2nd table above (the largest box).

Is there a difference between these numbers?

There appears to be a difference between all numbers – e.g. the number of victims of

crime in the rural area was expected to be 600.6, based on the sample size but it

actually was a lot lower at 413. This is the Descriptive part of the analysis. Step 2

covers the inferential part.

9

Step 2 In the 3rd table above (labelled Chi-square Tests). Look at the probability value under

Pearson Chi-Square – Asymp.Sig (this is the probability that these results occurred

by chance – so we want it to be as low as possible). If this value is lower than 5% or

in SPSS terms, .05 then we can conclude that the proportion of people who have been

victims of crime in urban areas is significantly different from the proportion of people

who have been victims of crime in rural areas. In this particular case, the reported

probability that the difference occurred by chance is .000, meaning very low. This is a

highly significant finding.

Interpreting the Chi-square for our chosen variables (Gender, Ever Accused of ASB)

Step 1: Have a look at the Count and Expected counts in the 2nd table.

Is there a difference between these numbers?

……………………………………………………………………………………….

If there is, we can proceed to the inferential part of the analysis.

Step 2: Find: the Pearson Chi-square value (Value), the degrees of freedom (df), and the

Asymp. Sig. (2-sided).

Identify whether the p value is: p<.05 or p=.05

If a p value is EQUAL to or LESS than .05 (p=.05), we can say that there is

a statistically significant association between the gender of the respondent and

whether that respondent has ever been accused of ASB.

However, if a p value is more than 0.05, there is no statistically significant

association.

Question 5

What are the implication of these results?

…………………………………………………………………………………………………

…………………………………………………………………………………………………

How to report a Chi-square

Chi-square statistics are reported with degrees of freedom and sample size in parentheses, the

Pearson chi-square value (rounded to two decimal places), and the significance level.

For example:

The percentage of participants that reported a fear of crime was not associated with gender,

chi-square (1, N = 90) = 0.89, p = .35.

Important: This is a fictitious example. It is not the result for Chi-square for your survey

respondents.

?

?

Remember: SAVE your OUTPUT file in SPSS and in MS Word

Reset the variables

10

RESEARCHING CRIMINOLOGY 2

WORKBOOK FOR WEEK 9

2014

(Computer practical 4)

ANALYSIS OF COMBINED GROUP DATA:

LARGE DATA SET

IMPORTANT

For Artefact 2 (the report on the group research project), you must use only:

– the Large Data Set 2014; and

– the data analysis that you have completed using this Large Data Set 2014.

Step 1: Log-in using your UoP log-in

Step 2: Open SPSS using the MyApps programme launcher (Application Jukebox Player)

Step 3: Minimize SPSS window

TASK 1: ACCESS THE LARGE DATA

SET SPSS FILE

1.1.

1.2.

1.3.

1.4.

1.5.

1.6.

1.7.

1.8.

1.9.

Log-in to Moodle

Open the site for Researching Criminology 2

Locate the section: Resources for Group Research Project

Locate the folder: Survey 2014

Open the folder; and find the data file: Large Data Set 2014

Open this file

The file should open in SPSS

Save the file in SPSS in the folder on your Student Drive that you created in the

Computer Practical 1.

Keep the file name the same.

Log out of Moodle

1

TASK 2:

SAMPLE CHARACTERISTICS

Task 2.1. Exploring sample characteristics (nominal data – frequencies)

Sample size

Gender (Qu1)

Level of Study (Qu4)

Full-time/Part-time (Qu6)

Complete the following questions.

Note: For Artefact 2, you need to decide how you are going to display the answers to the

questions for Task 2. Tables and/or graphs are not always suitable. For example, you could

write out the answer in a single sentence.

Question 2.1.

Size of N

What is the total number of respondents for all of the seminar groups? …………….

Question 2.2

Generate frequency tables for the variables:

Gender (Qu1)

Level of Study (Qu4)

Full-time/Part-time (Qu6)

(a) Gender (Qu1)

The University of Portsmouth reported that in December 2013, the student population

comprised:

Female 45%

Male 55%

http://www.port.ac.uk/media/why-portsmouth/institution/UoP-Facts-and-Figures2013_14.pdf

What is the gender distribution for our survey respondents?

Female ……..

Male ……..

How does this gender distribution compare with the UoP figures?

………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

2

(b) Level of study (Qu4)

What is the Level of Study distribution for our survey respondents?

(c) Full-time/Part-time (Qu5)

The University of Portsmouth reported that in December 2013, the student population

comprised:

Full-time 83%

Part-time 17%

http://www.port.ac.uk/media/why-portsmouth/institution/UoP-Facts-and-Figures2013_14.pdf

What is the Full-time/Part-time distribution for our survey respondents?

F/T ……..

P/T ……..

How does the full-time/part-time distribution of our survey respondents compare with

the UoP figures?

………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

Task 2.2. Generating sample characteristics:

Housing type (Qu3A)

Occupational size: Privately rented, shared with other students (Qu3B)

Generate frequency tables for all of the above variables.

Generate graphs for these variables (bar graph or pie chart)

Question 2.2.

What do these tables and graphs tell us about the types of housing for the majority of our

respondents?

………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………..

SAVE THIS OUTPUT FILE as an SPSS OUTPUT FILE

and as a MS Word file

in your folder: Researching Crim 2 Computer Practicals

REMEMBER TO GIVE THE FILE A NAME YOU CAN REMEMBER

and

RESET all variables in the ‘Analyse’ Dialogue window

3

TASK 3:

STUDENTS’ EXPERIENCES OF ASB

Task 3 Generate frequency tables for the following questions from Section C of the survey

questionnaire: Your experience of Anti-Social Behaviour (ASB)

Q. 11 (ASB Household)

Q. 18 (ASB Neighbours)

Q. 25 (ASB Portsmouth)

Question 3.1

What do these tables tell us about:

– the extent to which our sample of respondents have been victims of ASB?

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

TASK 4:

STUDENTS AS PERPETRATORS OF

ASB

Task 4 Generate frequency tables for:

– Extent to which Portsmouth public perceives students as perpetrators of ASB

(Qu9)

– Whether respondent ever accused of ASB when a student (Qu32A)

Question 4.1.

What do these tables tell us about:

– the extent to which Portsmouth public perceptions of the perpetrators of ASB (according

to our sample of respondents)?

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

– the extent of ASB among our sample of respondents?

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

SAVE THIS OUTPUT FILE (SPSS and MS Word)

and

RESET all variables in the ‘Analyse’ Dialogue window

4

TASK 5:

GENDER DIFFERENCES IN

PERCEPTIONS OF ASB

Independent-samples t-test

?

We are going to use an independent-samples t-test to compare whether there is any

significant difference between female and male respondents in terms of the extent

to which they consider certain behaviours to be Anti-Social Behaviour.

?

The independent-samples t-test is a parametric test that compares means for two

groups of cases, where the data collected on the groups is SCALE (or continuous

data). It enables us to evaluate whether there are any statistically significant

differences between groups of cases. We are going to group cases by the

characteristic:

– Gender (male/female)

Aim : To establish whether there are any statistically significant differences between the

men and women in our survey with regard to the extent to which they consider types

of behaviour to be ASB.

For this seminar, we will look only at the following 4 behaviours:

7H: People being drunk in a public place

7J: Using an imitation firearm/airgun in a public place

7M: Violent behaviour towards others

7T: Young people engaging in ‘tombstoning’

?

In the Tool Bar: click on Analyse > Compare Means > Independent-Samples T test

Move each of the dimensions (see above) into the Variables box.

Select Gender as your Grouping variable.

Click on ‘Define groups’ and enter 1 as a value for ‘Group 1’ and 2 as a value for

‘Group 2’.

Click on Continue and then click on OK.

The results of the t-test analysis will now appear in the Output window.

Interpreting the t-test is in two parts:

(1) Levene’s test for Equality of Variance tests the assumption that the two

populations being compared are of equal variance.

If this value (Sig.) is more than .05, then you refer to the ‘Equal variances

assumed’ row.

If the value (Sig.) is less than .05, then you refer to the ‘Equal variances not

assumed’ row.

5

(2) The t-test:

For each of our selected behaviours, find:

– the correct row; and then

– the t value (t) , the degrees of freedom (df), and the 2-tailed significance value

[Sig. (2-tailed)] (p value).

Note: When an SPSS Output files reports p = .000, then we can report this as p < .001

Identify which of the behaviours have p values [Sig. (2-tailed)] that are:

p<0.05 or p=0.05

If a p value is EQUAL to or LESS than 0.05 (p=0.05), we can say that there is

STATISTICALLY SIGNIFICANT DIFFERENCE between the means and therefore there

is a significant difference between the perceptions of males and females of the selected

behaviours.

However, if a p value is more than 0.05, there is no significant difference.

How to report a t-test

t-tests are reported with the degrees of freedom in parentheses, the t statistic value

(rounded to two decimal places) and the significance level.

For example:

There was a significant effect for gender, t(54) = 5.43, p < .01, with men (M 3.6, SD 1.2)

receiving higher scores than women (M 2.1, SD 1.01).

Important: This is a fictitious example. It is not the result for our T Tests.

Question 5

Report the results for each of the t-tests.

7H: People being drunk in a public place

……………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………

7J: Using an imitation firearm/airgun in a public place

……………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………

7M: Violent behaviour to others

……………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………

7T: Young people engaging in ‘tombstoning’

……………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………

Note: For Artefact 2, you must provide the result for at least one t-test.

? SAVE YOUR OUTPUT FILE (SPSS and MS Word)

? RESET all variables in the ‘Analyse’ Dialogue window

6

TASK 6:

ASSOCIATION BETWEEN

GENDER

and

STUDENTS’ EXPERIENCE OF ASB

?2 (Chi-square test)

?

?2 or the Chi-square test for independence (abbreviated to: Chi-square test) is a

non-parametric test that is used when you want to explore the relationship

between two NOMINAL (or categorical) variables. Each of these variables can have

two or more categories. The test compares the frequencies or proportions of cases

that occur in each of these categories, with the values that would be expected if

there was no association between the two variables being measured. The test is base

on a table known as a crosstabulation.

?

In essence, a Chi-square test determines whether the observed values are

significantly different from those expected. The expected values are determined by

assuming that the phenomena in question are distributed equally.

Aim : To establish whether there are any statistically significant association between: those

respondents who have been experienced ASB and those respondents who have not

been experienced ASB, in terms of gender.

?

Click on: Analyze > Descriptive Statistics > Crosstabs

Move Gender (Qu1) into the Rows box.

Move the following variables into the Columns box:

Q. 11 (ASB Household)

Q. 18 (ASB Neighbours)

Q. 25 (ASB Portsmouth)

Click on: Cells

In Cells Display window, under Counts select Observed and Expected.

Still in Cells Display: – under Percentages, select Column

– under Residuals, select Unstandardized and Adjusted

Standardized.

Click on: Continue.

Click on: Statistics

In the Crosstabs: Statistics window, click on Chi-square

Click on: Continue

Click on OK

The results of the chi-square analysis will now appear in the Output window.

7

Interpreting the Chi-square for our chosen variables

Step 1: Have a look at the Count and Expected counts in each Crosstab table.

Is there a difference between these numbers?

……………………………………………………………………………………….

If there is, we can proceed to the inferential part of the analysis.

Step 2: For each variable, in the Chi-Square Tests table, find:

the Pearson Chi-square value (Value), the degrees of freedom (df), and the

Asymp. Sig. (2-sided) (p value)

Identify whether the p value is: p<.05 or p=.05

Note: When an SPSS Output files reports p = .000, then we can report this as p < .001

If a p value is EQUAL to or LESS than .05 (p=.05), we can say that there is a statistically

significant association between the gender of the respondent and whether the respondent

has experienced ASB in a particular context (household, neighbours and/or other parts of

Portsmouth).

However, if a p value is more than 0.05, there is no statistically significant association.

How to report a Chi-square

Chi-square statistics are reported with degrees of freedom and sample size in parentheses,

the Pearson chi-square value (rounded to two decimal places), and the significance level.

For example:

The percentage of participants that reported a fear of crime was not associated with gender,

chi-square (1, N = 90) = 0.89, p = .35.

Important: This is a fictitious example. It is not the result for Chi-square for your survey

respondents.

Question 6

Report the result for the Pearson Chi-square test for

Q. 11 (ASB Household)

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

Q. 18 (ASB Neighbours)

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

Q. 25 (ASB Portsmouth)

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

? SAVE YOUR OUTPUT FILE (SPSS and MS Word)

? RESET all variables in the ‘Analyse’ Dialogue window

8

TASK 7:

ASSOCIATION BETWEEN

GENDER

and

THOSE ACCUSED OF ASB/NOT ACCUSED OF ASB

?2 (Chi-square test)

Aim : To establish whether there are any statistically significant association between: those

respondents who have been accused of ASB and those respondents who have not

been accused of ASB, in terms of gender.

Note: This is an analysis that is in addition to those that relate to the main aims of the

research project and that we thought might be interesting.

?

Click on: Analyze > Descriptive Statistics > Crosstabs

Move Gender (Qu1) into the Rows box.

Move EverAccussed (Qu32A) into the Columns box

Click on: Cells

In Cells Display window, under Counts select Observed and Expected.

Still in Cells Display: – under Percentages, select Column

– under Residuals, select Unstandardized and Adjusted

Standardized.

Click on: Continue.

Click on: Statistics

In the Crosstabs: Statistics window, click on Chi-square

Click on: Continue

Click on OK

Interpreting the Chi-square for our chosen variables (Gender, Ever Accused of ASB)

Step 1: Have a look at the Count and Expected counts in the 2nd table.

Is there a difference between these numbers?

……………………………………………………………………………………….

If there is, we can proceed to the inferential part of the analysis.

Step 2: Find: the Pearson Chi-square value (Value), the degrees of freedom (df), and the

Asymp. Sig. (2-sided).

Identify whether the p value is: p<.05 or p=.05

Note: When an SPSS Output files reports p = .000, then we can report this as p < .001

9

If a p value is EQUAL to or LESS than .05 (p=.05), we can say that there is a statistically

significant association between the gender of the respondent and whether the respondent

has experienced ASB in a particular context (household, neighbours and/or other parts of

Portsmouth).

However, if a p value is more than 0.05, there is no statistically significant association.

How to report a Chi-square

See the guidance for Task 6

Question 7

Report the result for the Pearson Chi-square test (Gender, Ever Accused of ASB).

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

? SAVE YOUR OUTPUT FILE (SPSS and MS Word)

? RESET all variables in the ‘Analyse’ Dialogue window

Note: For Artefact 2, you must provide the result for at least one Pearson Chi-square test.

10

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