Mr. B, the manager of the retail store in Exercise 12.55, has seen the effect day has on the mean number of customers per day and is now wondering if day has a similar effect on total cost of items purchased.

a. Do you think “day of week” has an effect on the mean total cost of items purchased per day? Equivalently, do you think the mean total cost of items purchased per day is the same for all days? If not, which days do you believe will be different? Explain.

b. Construct a dotplot for the total cost of items purchased per day for each different day of the week.

c. Does the dotplot in part b support your conjectures in part a? Explain.

d. Use the ANOVA technique to answer the question,

“Does day of the week affect the mean total cost of items purchased per day?” Use

  0.05.

e. Explain any differences and similarities between your answer in part a and the answer found in d.

f. Explain any differences and similarities between the answers found for Exercises 12.55, 12.56, and 12.57. Do the similarities seem reasonable?
What does this imply about these variables?