the following data give the time (in minutes) taken by 20 taxpayers to complete the Form1040.

40

53

63

37

45

55

31

48

29

53

46

35

45

60

39

50

38

40

42

51

(a)What is the underlying population, the variable of interest? Is the variable qualitative or quantitative? What is the highest level of measurement that can be used for these data?

(b)Construct a stem-and-leaf plot.Make your comment on the shape of the distribution:Can we say that the data is from a normally distributed population?

(c)Calculate the mean and standard deviation of these sample data.

(d)Based on the sample data, construct a confidence interval at the confidence level of95% for the mean time taken to complete the 1040 Form for all taxpayers.