The General Social Survey collects data on demographics, education, and work, among many other characteristics of US residents. The histograms below display the distributions of hours worked per week for two education groups: those with and without a college degree. What is the p-value assessing the null hypothesis that the number of hours worked per week by all Americans without a college degree is greater than for those with a college degree? Summary information for each group is shown in the tables.

Select one:

a.

0.007

b.

0.004

c.

Indeterminate

200 College degree 100 College degree 0 Mean 41.8 hrs O 20 40 60 80 SD 15.1 hrs n 505 250 No college degree No college degree Mean 39.4 hrs 125 SD 15.1 hrs n 667 0 20 40 60 80 Hours worked per week