Mr. B, the manager of the retail store in Exercise 12.36, has seen the effect month has on the mean number of customers per day and is now wondering about the effect day of the week has on the mean number of customers per day.

Is the mean number of customers per day affected by the day of the week? Or equivalently, “Is the mean number of customers per day the same for all days of the week?” versus “Is there at least one day of the week when the mean number of customers per day is significantly different from the others?” The following computer output resulted from analysis of the data.

(Day Code: 1 Monday, 2 Tuesday, . . . , 6 Saturday.)

Inspect the preceding dotplot for number of customers per day for the 6 weekdays and the ANOVA output for number of customers versus day of week. Look for evidence that leads to the conclusion, “Not all days have the same mean number of customers per day.”

a. Describe the graphical evidence found and discuss how it shows that not all days of the week are the same. Which day or days appear to be different from the others?

b. Describe the meaning and source of the 5 points located to the right and separate from the rest of the data. (Hint: Look at the data.)

c. Describe the numerical evidence found and discuss how it shows that not all days are the same.

d. Can you tell which days are different based on the numerical evidence? Explain.

e. Use your calculator or computer to perform the ANOVA shown and verify the results.

Transcribed Image Text:

N Day m in Dotplot of Customers vs Day 600 900 1200 1500 Customers 1800 2100 2400 One-way ANOVA: Customers versus Day Source DF SS MS F P Day 5 1604566 320913 2.15 0.072 Error 56 8344274 149005 Total 61 9948840