Dr. Christine Pereira
Part 2: Summarising Data using Descriptive Statistics
BEEC
Dr. Christine Pereira Academic Skills Team (ASK) ask@brunel.ac.uk
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 (2014-15)
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Click here
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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Representing Data Graphically
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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All variables listed here
Build your chart here
Select chart format
Select chart type
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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Simple Bar Chart
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Pie Chart
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Create a Bar chart and/or Pie chart for the variable Ethnicity
1
What is your ethnicity? (please tick one)
White/European Asian West Indian African Other
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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Clustered Bar Chart
Dr. Christine Pereira
Stacked Bar Chart
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Create a Clustered bar chart to summarise Organisational Commitment by Gender
1
“I am very committed to this organisation.� Strongly Disagree
Disagree
1
2
Gender (please tick one)
Dr. Christine Pereira
Neutral
Agree
Strongly Agree
3
4
5
2
Male Female
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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Simple Histogram
Dr. Christine Pereira
ASK at Brunel (2014-15)
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1D Boxplot
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Create a Histogram or Boxplot to summarise Annual Income
1
What is your gross annual income?
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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Simple Scatterplot
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Create a Scatterplot to summarise the relationship between Annual Income and Age
1
What is your gross annual income?
2
Age last birthday (in years)?
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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Simple Bar Chart
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Simple Line Chart
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Create a Chart of means to summarise employees total competency at all 3 time points: Start, 6 months, 12 months
1
Competency score at start of job.
2
Competency score at 6 mos. on the job.
3
Competency score at 12 mos. on the job.
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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Simple Bar Chart
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Simple Line Chart
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Create a Chart of means to summarise the relationship between Annual Income and Rated Skill
1
What is your gross annual income?
2
Rated Skill of work: Unskilled 1
Dr. Christine Pereira
Semi-Skilled 2
Fairly Skilled 3
ASK at Brunel (2014-15)
Highly Skilled 4
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Right Click -> Edit Content -> In Separate Window
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Reduce chart size and Apply changes
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Right Click to view more options
E.g., Transpose Chart Dr. Christine Pereira
ASK at Brunel (2014-15)
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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
Dr. Christine Pereira
ASK at Brunel (2014-15)
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More Go In
resources available on Blackboard
to Academic Skills under My Organisations
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
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Representing Data Numerically
Dr. Christine Pereira
ASK at Brunel (2014-15)
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(All Descriptives)
(Limited Descriptives)
(Limited Descriptives)
Mean, Median, Mode
Dr. Christine Pereira
ASK at Brunel (2014-15)
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(All Descriptives)
(Limited Descriptives)
(Limited Descriptives)
Mean, Median, Mode Stdev, Variance Range, Percentiles, Min, Max, etc‌
Dr. Christine Pereira
ASK at Brunel (2014-15)
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(All Descriptives)
(Limited Descriptives)
(Limited Descriptives)
Mean, Median, Mode Frequency Table, Frequency Table, Stdev, Variance Median, Mode Mode Range, Percentiles, Min, Max, etc‌
Dr. Christine Pereira
ASK at Brunel (2014-15)
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(All Descriptives)
(Limited Descriptives)
(Limited Descriptives)
Mean, Median, Mode Frequency Table, Frequency Table, Stdev, Variance Median, Mode Mode Range, Percentiles, Min, Max, etc‌
Treating ORDINAL data like SCALE data Dr. Christine Pereira
ASK at Brunel (2014-15)
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ď‚ž Ordinal ď‚Ą
data
Mean and stdev OR frequencies and percentages?
Mean = 3.28 Stdev = 1.41 1
2
3
4
5 Strongly Agree
Strongly Disagree
Disagree
Neutral
Agree
12%
22.7%
21.3%
13.3%
Dr. Christine Pereira
ASK at Brunel (2014-15)
30.7%
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Use descriptive statistics to summarise responses for Annual Income
1
What is your gross annual income?
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use to obtain Descriptives Frequency tables Charts • Bar • Pie • Histogram
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use descriptive statistics to summarise responses for Annual Income
Untick
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use descriptive statistics to summarise responses for Annual Income
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014)
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Two methods: 1. ‘Explore’ option 2. Split file, then ‘Frequencies’ option We will use the 2nd method. Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use descriptives to summarise the relationship between Annual Income split by Gender
1
What is your gross annual income?
2
Gender (please tick one)
Dr. Christine Pereira
Male Female
ASK at Brunel (2014-15)
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Dr. Christine Pereira
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Output for males and females will be in one table
Separate output tables for males and females
Categorical Variable File must be sorted! Dr. Christine Pereira
ASK at Brunel (2014-15)
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The file is sorted All females are listed first, then all males
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Now get stats for Annual Income • Use ‘Frequencies’ • Output will be split by Gender
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use descriptives to summarise the relationship between Annual Income split by Gender
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use descriptives to summarise the relationship between Annual Income split by Gender
Split File Option to Compare Groups Output for males and females is in one table
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Separate output tables for males and females
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use descriptives to summarise the relationship between Annual Income split by Gender
Split File Option to Organise Output by Groups Separate output table for males and females Dr. Christine Pereira
ASK at Brunel (2014-15)
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When finished, return the file to normal.
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use descriptive statistics to summarise responses for Organisational Commitment
1
“I am very committed to this organisation.� Strongly Disagree 1
Dr. Christine Pereira
Disagree 2
Neutral
Agree
Strongly Agree
3
4
5
ASK at Brunel (2014-15)
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Use to obtain Descriptives Frequency tables Charts • Bar • Pie • Histogram
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use descriptive statistics to summarise responses for Organisational Commitment
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use descriptive statistics to summarise responses for Organisational Commitment
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Percent Out of the total sample size (e.g., 70)
14 out of 70 is 20.0%
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Percent Out of the total sample size (e.g., 70)
16 out of 70 is 22.9%
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Percent Out of the total sample size (e.g., 70)
68 out of 70 is 97.1%
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Valid Percent Out of the total number of responses (e.g., 68)
14 out of 68 is 20.6%
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Valid Percent Out of the total number of responses (e.g., 68)
16 out of 68 is 23.5%
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Cumulative Percent Sum of Valid Percents
Same as 1st Valid Percent Dr. Christine Pereira
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Cumulative Percent Sum of Valid Percents
Sum of 1st two Valid Percents Dr. Christine Pereira
ASK at Brunel (2014-15)
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Cumulative Percent Sum of Valid Percents
Sum of 1st three Valid Percents Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use a cross tabulation table to summarise Organisational Commitment by Gender
1
“I am very committed to this organisation.� Strongly Disagree
Disagree
1
2
Gender (please tick one)
Dr. Christine Pereira
Neutral
Agree
Strongly Agree
3
4
5
2
Male Female
ASK at Brunel (2014-15)
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Use to obtain Crosstabs table • Observed count or % • Expected count
Crosstab statistics • Chi-square • Correlations
Clustered bar charts
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use a cross tabulation table to summarise Organisational Commitment by Gender
Observed count Frequency observed in the sample
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use a cross tabulation table to summarise Organisational Commitment by Gender Row % % of participants Uses row totals
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use a cross tabulation table to summarise Organisational Commitment by Gender Total % % of participants Uses sample size
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use a cross tabulation table to summarise Organisational Commitment by Gender Column % % of participants Uses column totals
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use a cross tabulation table to summarise Organisational Commitment by Gender
4 of 38 Females Strongly Agreed
10.5% of females
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use a cross tabulation table to summarise Organisational Commitment by Gender
8 of 30 Males Agreed
26.7% of males
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Use a cross tabulation table to summarise Organisational Commitment by Gender
19 of 68 Respondents were Undecided
27.9% of respondents
Dr. Christine Pereira
ASK at Brunel (2014-15)
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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.
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Short video tutorials on all these topics
Dr. Christine Pereira
ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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Short video tutorials on all these topics
Dr. Christine Pereira
ASK at Brunel (2014-15)
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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.
Dr. Christine Pereira
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Dr. Christine Pereira
ASK at Brunel (2014-15)
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