chapt 5 practices NIBRS-GSS / CJ STATS

CJ 317 CJ Statistics

Chapter 5 – GSS Exercises

1. Education is an important issue. Using the General Social Survey, find the mean and standard deviation for the highest year of school completed (EDUC).

a. Using this mean and standard deviation, what percentage of Americans are expected to complete 16 or more years of education (16 or above)?

b. What percentage of Americans are expected to report 10 or fewer years as their highest year of school completed?

c. What is the probability of selecting at random a person in America who completes more than 12 years of school (13 or more)?

2. Using the frequencies procedure (ANALYZE, DESCRIPTIVE STATISTICS, FREQUENCIES), request a histogram of television viewing data from the General Social Survey (TVHOURS) with the normal curve overlay (from the Charts button), as well as the mean and standard deviation (from the Statistics button).

a. Comment on the closeness of the actual distribution to the normal curve.

b. Based on the normal distribution (using the z score and Table A), what is the probability that a person watches 3 or more hours of television per day?

3. Using the frequencies procedure (ANALYZE, DESCRIPTIVE STATISTICS, FREQUENCIES), request a histogram of total family income (INCOME06) from the General Social Survey with the normal curve overlay (from the Charts button), as well as the mean and standard deviation (from the Statistics button).

a. Comment on the closeness of the actual distribution to the normal curve.

b. Based on the normal distribution (using the z score and Table A), what is the probability that a family has an in- come of $75,000 to $89,000 (21 on the scale)?