SOC 201: Introductory Sociological Statistics

***Homework Assignment 11***

Please use this form to record your answers and include any work that you would like to show the grader (you can paste in photos or scans of your hand-written work if you like). Save this document in Word, rtf, txt, or pdf format and submit the document for grading via the course website. THESE ARE THE ONLY FILE FORMATS THAT WILL BE ACCEPTED.

This homework is out of 3 points, worth 3 percent of your final grade.

Note that almost all examples used below are fake. I made up them up for pedagogical purposes only.

1. A teaching assistant has selected a random sample of students in a statistics class and compared the quiz performance of two groups within this sample: one group of students who regularly attended lectures and one group who did not regularly attend lectures. She ultimately wants to know if attending lectures helps students' quiz performance. Her data show that 22 of the 30 members of the first group (lecture attendees) passed the quiz, only 10 of the 28 members of the second group (non-attendees) passed the quiz.

• (0.75 points) Create two-way table of quiz performance (passed / did not pass) by attendance status (attended / did not attend).

• (0.125 points) Describe, in percentages, the marginal distribution for quiz performance. Feel free to write these percentages into your table instead of describing them below.

• (0.125 points) Describe, in percentages, the conditional distribution of quiz performance within each independent variable. Feel free to write these percentages into your table instead of describing them below.

• (0.25 points) According to the data, does there appear to be an association between quiz performance and lecture attendance? Support your argument by referring to the conditional distribution of quiz performance across attendance status.

• For the table in Question 1, use a chi-square test and .05 alpha level to test the null hypothesis that there is no association between quiz performance and attendance status in the population of statistics students. Make sure to report...

a. (0.125 points) The critical value of the test statistic:

b. (0.25 points) The value of the test statistic calculated from the sample data:

c. (0.125 points) Your decision about the null hypothesis:

d. (0.25 points) An interpretation of the meaning of your decision:

• A sociologist is trying to test whether life stage affects experience of arrest. In order to test the hypothesis that there is an association between life stage and being arrested, you conduct a survey of 100 people and ask them if they have been arrested in the past year. Below is a table containing your results.