AuSSA Data Subset Tutorial Exercise 2:
Measures of Central Tendency
The value of measures of central tendency is that they summarise our data to just one
number, according to how the data are dispersed. There are several methods of
obtaining measures of central tendency in SPSS, and two are outlined below. Refer to
page 292–3 of your text for definitions of the main terms associated with measures of
central tendency: Mean; Median; Mode; and Standard Deviation.
Method 1:
1. Click the ‘Analyze’ button in from the menu toolbar at the top of the data screen
2. Select and click ‘Descriptive Statistics’ from the drop down list
3. Select and click ‘Frequencies’ from the drop down list
4. Select variable (v295) How Many Years of Education have you completed and
move it to the variable box
5. Click the ‘Statistics’ button at bottom of box and tick: Mean, Median Mode from
the Central Tendency list
7. Click ‘Continue’ at the top of the statistics box
8. Click ‘OK’. Your measures of central tendency and your frequency distribution are
now displayed in the output window
Questions for Method 1:
1. What are the mean _____median______ and mode _______years of education?
2. Is there much of a difference between these measures? How would you explain the
differences?
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Method 2:
1. Click the ‘Analyze’ button from the menu toolbar at the top of the data screen
2. Select and click ‘Descriptive Statistics’ from the drop down list
3. Select and click ‘Explore’ from the drop down list
4. Select variable (v295) How Many Years of Education have you completed and
move it to the dependent list box
5. Click the ‘statistics’ point at the bottom of the variable list
6. Click ‘OK’. Your descriptive measures, including measures of central tendency are
now displayed in the output window
Walter, M. (ed.) 2006, Social Research Methods: an Australian perspective, Oxford University Press: Melbourne.
Questions for Method 2:
3. What is the difference in the information included in the outputs from Method 1
compared to Method 2?
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4. What do you think might be the analysis benefits of each method?
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5. Can you explain some of the other descriptive statistics included in the output for
the method 2 analysis?
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6. Statistical analysis is not just about generating statistical ‘results’. The important
social science research work is how we interpret these results to increase our
understanding of social phenomena. So, using these statistics, including the measures
of central tendency, write a short paragraph that summarises what the AuSSA data tell
us about the level of education among the Australian population. Add to your results
(and your interpretation) by also running a frequency distribution (as per exercise 1)
on the variable (v296) R: What is the highest level of education you have completed?
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Do you think the story about education levels contained within these data would
change if we divided our analysis by gender?
Note:
Measures of central tendency are usually, but not exclusively, used with continuous
variables. Continuous variables are those whose categories of response are in a
continuous run of numbers format—that is, years of education, age in years, number
of children in the household.
Walter, M. (ed.) 2006, Social Research Methods: an Australian perspective, Oxford University Press: Melbourne.