SOC 353: Sociological Research: Analysis
Exam #2 Extra Credit
Due Date: 12 p.m. on November 12, 2019 (via Canvas)
Directions: Answer the following questions. Please show all of your work. If your exam #2 grade
was an 85 or below, then each of the two questions is worth 7.5 points (for a total of 15 points). If
your exam #2 grade was an 86 or above, then each question is worth (100 – G2)/2 points, where
G2 is your original exam #2 grade. The answer to each sub-question should be 1 to 3 complete
sentences in length.
1.) A researcher is interested in studying whether income levels vary between people who
attended four-year for-profit colleges versus two-year public colleges. Using the 2014
wave of the General Social Survey (GSS), they ask the following question: “Do U.S. adults
who attended a four-year for-profit college go on to make a different amount of money
than U.S. adults who attended a two-year public college?” The dependent variable is the
respondent’s current yearly income in U.S. dollars. The independent variable is a
dichotomous variable that indicates whether the respondent attended a four-year for-profit
college or a two-year public college. In total, 19 of the sampled U.S. adults attended a fouryear
for-profit college and 70 attended a two-year public college.
The mean income for people who attended a four-year for-profit college is $18,677.28 with
a standard deviation of $2, XXXXXXXXXXThe mean income for people who attended a two-year
public college is $19,249.41 with a standard deviation of $1, XXXXXXXXXXUsing an a = .01, does
the researcher have enough evidence to conclude that, in the U.S. adult population, income
levels likely vary depending on whether someone attended a four-year for-profit college or
a two-year public college? Explain. Be sure to follow the “five step” system for hypothesis
testing outlined in class and in the textbook.
2.) Below are some descriptive statistics for a variable in the 2014 GSS called “tvhours.” The
variable indicates the average number of hours per day the respondent spends watching
TV. Calculate a 99.9% confidence interval around the mean and interpret it.
Variable | Obs Mean Std. Dev. Min Max
tvhours | 1, XXXXXXXXXX XXXXXXXXXX