The t statistic

Collect data from 10 females and 10 males on the number of shoes each person owns. In class, we will develop a script for you to explain what the purpose of the data collecton is (namely, to gather information to learn about statistical tests) and that the data are confidential. You will give this explanation to the people you interview, because they are entitled to informed consent.

After explaining the purpose of the question, you will ask this question, in these precise words:

Do not ask both members of a couple (spouses, for example), because this would violate the assumption of independence that is required for the t statistic.

You will then calculate a t statistic to determine if there is a significant (p < .05) effect for gender on number of shoes owned, and write up your findings in APA style.

Create a graph showing the mean and standard deviations for number of shoes owned. Do this in the same manner as you did for the observation lab graphs. The graph will become part of your study.

Writing Up the Study

In APA style, write an Abstract, Method, Discussion and Results sections. You should include your hypothesis (your hypothesis, which is your prediction; not the null hypothesis) in the Abstract. Your report should answer the following questions:

1. Do men and women differ in the number of shoes owned, and is the difference significant? [Results section]
2. Do your results support the null hypothesis or the alternate hypothesis? If so, why? If not, why might it not match? [Discussion section]
3. What might be sampling problems with this observation, and how could you change the sampling procedures to avoid the problems? [Discussion section]

Here is the form I will use to assess your papers.

When You Finish

Email the raw data in a comma-separated value (.csv) file to the instructor. I suggest that you have it in a format like this:

gender,shoes
m,5
f,4
m,6

Name your file in the form like tstatnnnn.csv, where nnnn is your four-digit ID number.

Also, email the writeup to the instructor. It should have a name like tstatnnnn.rtf or tstatnnnn.odt, depending on whether you have saved the file in RTF format or in OpenOffice.org format. Again, nnnn is your four-digit ID number.