Tracy works in a drugstore photo-developing department. Over time, Tracy felt that the number of rolls of film brought in for development varied among the days of the week.

Were the weekends having an effect one way or another? Tracy decided to keep a daily record of the number of rolls of film dropped off for development for 4 weeks. Her results follow.

M Tu W Th F Sa Su 33 43 27 28 26 40 18 21 23 29 39 32 21 7 47 36 14 21 17 12 5 38 41 47 14 33 8 11

a. Using a one-way ANOVA, test the claim that the mean number of rolls of film dropped off is not the same for all 7 days of the week. Use a level of significance of 0.05.

b. Explain the meaning of the conclusion in part

a. Does the conclusion tell you which days are different? which days have the larger means?

c. Construct a side-by-side dotplot of the data.

Explain how the multiple dotplot coupled with the hypothesis test in part a help identify the difference between days.

d. How might the drugstore use this information?

e. Could there be other factors affecting these results?
If so, name a few.