SUNY College at Buffalo Sociology 301 (Social Statistics)
Homework #7: To be due at the beginning of Chapter 8
Dr. ZHANG Jie

Submit your work on a Word file with the homework #, your name, and the date on top of it. The highest possible score for this homework is 10.

Essay Question 1:

What is a sampling error and what is a pure chance?  Illustrate each of them with an example.

Essay Question 2:

What is null hypothesis and what is a research hypothesis?  Discuss their relationship.  What do we really mean when we say we reject the null hypothesis?  Illustrate it with an example.

Essay Question 3:

What is an alpha and what is a confidence level?  Discuss their relationship (in terms of 100%).  What is a significance level?

Essay Question 4:

In comparing two means, we have calculated a t value of 1.84.  If we know that the df is 36, and allow a signicance level of .05, what should we do on the research hypothesis?  Explain your answer with as many sentences as you can.

Computer Assignment:

Find a data set from the SPSS program and identify two variables from the same sample or the same variable from two samples.  Run a t test to compare the two means.  Make a decision on the research hypothesis.  Write a paragraph on your work and decision.