Recall that the file P4_1.XLS contains a data set that represents 30 responses from a questionnaire concerning the president’s environmental policies. Each observation lists the person’s age, gender, state of residence, number of children, annual salary, and opinion of the president’s environmental policies. 

a. Use Excel’s auto filter tool to identify all respondents who are female, middle-aged, and who have two children. What is the average salary of these respondents?

b. Use Excel’s auto filter tool to identify all respondents who are elderly and who strongly disagree with the president’s environmental policies. What is the average salary of these respondents?

c. Use Excel’s auto filter tool to identify all respondents who strongly agree with the president’s environmental policies. What proportion of these individuals are young?