basics of spss, part 2

Part 2:

Summarising Data using Descriptive Statistics D

r. C

hristine P

ere

ira

Choose appropriate graphical summaries

Charts and graphs in SPSS

Choose appropriate numerical summaries

Descriptive statistics in SPSS

Frequency tables in SPSS

Dr. Christine Pereira ASK at Brunel (2014) 2

Log into Blackboard

Under “My Organisations” click “Academic Skills”

In the left column under “Workshop presentations”

Click Statistics and SPSS

Find the Basics of SPSS Workshop

Download and save the SPSS data file: EmployeeSurvey.sav


Representing Data Graphically


All

variables

listed here

Select

chart

type

Select

chart

format

Build your

chart here


Simple Bar Chart


Pie Chart


What is your ethnicity? (please tick one)

White/European

Asian

West Indian

African

Other

Create a Bar chart and/or Pie chart for the variable Ethnicity

1


Clustered Bar Chart Stacked Bar Chart


Create a Clustered bar chart to summarise

Organisational Commitment by Gender

“I am very committed to this organisation.”

Strongly Disagree Neutral Agree Strongly

Disagree Agree

1 2 3 4 5

1


Gender (please tick one)

Male

Female

2

Simple Histogram


1D Boxplot


Create a Histogram or Boxplot to summarise Annual Income

What is your gross annual income? 1


Simple Scatterplot


Create a Scatterplot to summarise the relationship between

Annual Income and Age


Age last birthday (in years)? 2


Simple Bar Chart


Simple Line Chart


Create a Chart of means to summarise employees total competency

at all 3 time points: Start, 6 months, 12 months

Competency score at start of job. 1

2 Competency score at 6 mos. on the job.

3 Competency score at 12 mos. on the job.


Simple Bar Chart


Simple Line Chart


Create a Chart of means to summarise the relationship between

Annual Income and Rated Skill


2 Rated Skill of work:

Unskilled Semi-Skilled Fairly Skilled Highly Skilled

1 2 3 4


Right Click -> Edit Content

-> In Separate Window


Reduce chart size

and Apply changes


Right Click to view more options

E.g., Transpose Chart


There’s much more in Chart Editor

You can change:

Colours

Fonts

Axis labels

Data labels

Insert trend lines

Rearrange (or remove) variables

…the list goes on


More resources available on Blackboard

Go to Academic Skills under My Organisations

In the left side column

Under Resources click on Statistics and SPSS

Here you can find videos, power point slides and

guides for charts and graphs in SPSS


Representing Data Numerically


(All Descriptives)

Mean, Median, Mode

(Limited Descriptives) (Limited Descriptives)


(All Descriptives)

Mean, Median, Mode

Stdev, Variance

Range, Percentiles,

Min, Max, etc…

(Limited Descriptives) (Limited Descriptives)


(All Descriptives)

Mean, Median, Mode

Stdev, Variance

Range, Percentiles,

Min, Max, etc…

(Limited Descriptives)

Frequency Table,

Median, Mode


Frequency Table,

Mode


(All Descriptives)

Mean, Median, Mode

Stdev, Variance

Range, Percentiles,

Min, Max, etc…


Frequency Table,

Median, Mode


Frequency Table,

Mode

Treating ORDINAL data

like SCALE data


Ordinal data

Mean and stdev OR frequencies and percentages?

Strongly

Disagree

Strongly

Agree

Neutral Disagree Agree

1 2 3 4 5

12% 22.7% 21.3% 13.3% 30.7%

Mean = 3.28

Stdev = 1.41

1.87 4.69


Use descriptive statistics to summarise responses for

Organisational Commitment



Disagree Agree

1 2 3 4 5

1


Use to obtain Descriptives

Frequency tables

Charts • Bar

• Pie

• Histogram



14 out of 70

is 20.0%

Percent Out of the total sample size (e.g., 70)


16 out of 70

is 22.9%



68 out of 70

is 97.1%



14 out of 68

is 20.6%

Valid Percent Out of the total number of responses (e.g., 68)


16 out of 68

is 23.5%

Valid Percent Out of the total number of responses (e.g., 68)


Same as 1st

Valid Percent

Cumulative Percent Sum of Valid Percents


Sum of 1st two

Valid Percents



Sum of 1st three

Valid Percents



Annual Income



Use to obtain Descriptives

Frequency tables

Charts • Bar

• Pie

• Histogram



Annual Income


Use a cross tabulation table to summarise




Disagree Agree

1 2 3 4 5

Gender (please tick one)

Male

Female

1

2


Use to obtain Crosstabs table

• Observed count or %

• Expected count

Crosstab statistics • Chi-square

• Correlations

Clustered bar charts





Observed count

Frequency observed

in the sample




Row %

% of participants

Uses row totals




Total %

% of participants

Uses sample size




Column %

% of participants

Uses column totals




4 Females

Strongly Agreed




8 Males

Agreed




19 Participants

were Undecided




4 of 38 Females

Strongly Agreed

10.5% of females




8 of 30 Males

Agreed

26.7% of males




19 of 68 Respondents

were Undecided

27.9% of respondents

Two methods:

1. ‘Explore’ option 2. Split file, then ‘Frequencies’

option We will use the

2nd method.



Use descriptives to summarise the relationship between

Annual Income split by Gender


2 Gender (please tick one)

Male

Female

Categorical

Variable

Output for males

and females will

be in one table

Separate output

tables for males

and females

File must

be sorted!


The file is sorted

All females are listed

first, then all males



Now get stats for Annual Income

• Use ‘Frequencies’

• Output will be split by Gender




Split File Option to

Compare Groups

Output for males and

females is in one table

Separate output

tables for males

and females





Split File Option to Organise Output by Groups

Separate output table for males and females


When finished, return

the file to normal.

Choose your numerical and graphical summaries

based on the level of measurement of each variable.

Likert scale data is ORDINAL not scale.

In a frequency table, use the Valid Percent rather

than the Percent.

In a crosstab table,

Choose the correct percentage(s) (row, column or total)

based on what you are trying to emphasize or draw

attention to.

Make sure you interpret the percentage(s) correctly.



Short video

tutorials on all

these topics

SPSS Survival Manual, 4th Edition (2010) by Julie Pallant.

SPSS Survival Manual, 5th Edition (2013) by Julie Pallant.

Discovering Statistics Using SPSS, 3rd Edition (2009) by

Andy Field.

Discovering Statistics Using SPSS, 4th Edition (2013) by

Andy Field.


basics of spss, part 2

Education