The manager of a local Costo store is in the process of making hiring decisions for selling mobile phone contracts. She believes that the sale of mobile phone contracts depends crucially on the number of hours clocked by male and female employees. She collects the weekly data on last year's sales of mobile phone contracts (Sale) along with work hours of male (Hours Males) and female (Hours Females) employees. A portion of the data is shown in the accompanying table.
Sale Hours Males Hours Females
59.....................30..................................32
65.....................33..................................36
⋮.........................⋮....................................⋮
64.....................35..................................35
a. Report the sample regression equation of the appropriate model.
b. At the 5% significance level, are the explanatory variables jointly significant? Are they individually significant? Use the p-value approach for the tests.
c. The manager would like to determine whether there is a difference in productivity of male and female employees. In other words, for the same work hours, whether the number of sales of mobile contracts varies between male and female employees. Conduct the appropriate test at the 5% level of significance. Provide the details.