Overview

 In lab today, you will be introduced to SPSS, the data analysis program that we will be using throughout the semester.  You are going to get familiar with starting up SPSS, entering data into the program, and making  histograms of the data.  You will also calculate the mean, median, and the variance of each distribution.

For Starters

Your TA will type in some data in SPSS's editor and will show you how to plot a histogram.  Then, your TA will also show you how to calculate the mean, median, and variance of the distribution.  Finally, the TA will show you how to import data from Excel to SPSS (this may prove useful in future projects, such as your papers).

Your Assignment

 First, enter in these three data sets (each data set has 20 observations).  You can think of these numbers as representing individual scores on a test, heights, or just about anything.

Set A

2 3 4 5 2 3 4 5 2 3 4 5 2 3 4 5 2 3 4 5

Set B

1 1 1 1 1 7 7 7 7 7 2 2 3 3 4 4 5 5 6 6

Set C

4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 5 5 5 5 20

You'll need to turn in the following information:

1) For each data set, calculate the mean, median, and variance.  Also print out a histogram of the data.

2)  What is the shape of each distribution?  Is it symmetric?   Is it skewed?

3)  Are there points in the distribution that fall far away from the rest of the points (that is, are there outliers)?  If yes, how does removing the outlier affect the mean, median, and variance.

4)  Where is the middle of each distribution?  What value do you think gives a good characterization of the middle of the distribution?

5)  How much variation is there in each distribution?  Are all of the values generally clustered closely around a single value or are the values very spread out?