Help Mr. B, the store manager in Exercises 13. 77 and 13. 78 (and Exercises 12.44–12.46), by analyzing the relationship between the numbers of items purchased daily and the total daily sales in the data from the first 10 months of the year.
a. Construct the scatter diagram for the data for January to October.
b. Describe the graphical evidence found and discuss the linearity. Are there any ordered pairs that appear to be different from the others?
c. What is the relationship between the number of items purchased per day and the total daily sales for the first 10 months of the year?
d. Is the slope of the regression line significant at a = 0.05?
e. Give the 95% prediction interval for the total daily sales that one would expect if the number of items purchased per day were 3000.