Measures of Central Tendency Lab by cuiliqing

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```									Measures of Central Tendency Lab
Lab

Objective: The objectives of this lab are:
 Learn to calculate measures of central tendency in SPSS.
 Learn to use SPSS to make group comparisons.
 Learn to use measures of central tendency to evaluate a research
question.

Directions: Use the data the GSS to perform the following tasks.

Demonstration: Graphing with SPSS

1. I will use the variable “educ” to demonstrate how to calculate the mode, median,
and mean using SPSS.
a. What is this variable measuring?
b. What is the level of measurement of this variable?

To calculate these measures of central tendency, do the following:
a. From the pull-down menus choose Analyze… Descriptive Statistics…
Frequencies
b. Choose the variable “educ” (HIGHEST YEAR OF SCHOOL
COMPLETED) and use the arrow to move it to the blank space.
c. Click on “Statistics…”
d. In the “Central Tendency” area make sure that the boxes next to mean,
median, and mode are checked.
e. Click “Continue” and then click “Okay”

Let’s take a look at our results:
a. Compare the mode, median, and mean to each other. What do they tell you
b. Which measure of central tendency is the most appropriate one to present?

2. Let’s suppose we were interested in comparing the measures of central tendency
for the variable educ for men and women (using the variable sex). We could split
the data file and tell SPSS that we want all statistics to be output as a comparison
between males and females.

To do this, we must do the following:
a. From the pull-down menu choose Data… Split File
b. Choose the variable “sex” (RESPONDENTS SEX) and use the arrow to
move it.
c. Make sure that the bubble next to “Compare Groups” is selected.
d. Click ok.

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Now let’s try estimating measures of central tendency again.
e. How is the data presented?
f. What do you notice about the differences in the measures of central
tendency for men and women?

Lab Exercise

3. In his book The Classless Society (2000) Paul Kingston argues that social class is
not a meaningful category in contemporary American society. He claims that
people having a common economic position (what are commonly called classes)
do not share distinct, life-defining experiences. In today’s lab we will test
Kingston’s theory by comparing subjective class designation to objective
measures of socioeconomic status.

We will use the following variables in our analysis: class, inccod98, polyviews,
and union.
a. What are each of these variables?
i. Use the GSS webpage to help you determine what these variables
are (http://webapp.icpsr.umich.edu/GSS/).
b. What are their levels of measurement?

To evaluate Kingston’s argument compare measures of central tendency for these
variables for different categories of subjective social class.
a. Which measure of central tendency is appropriate for each of these
variables?
b. How can we use these measures to make some kind of inference about
Kingston’s argument?

Choose another variable that you think might be useful for evaluating Kingston’s
argument. Calculate measures of central tendency for your variable and interpret
the results.

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