Chapter 12, Problem 80BITH

Use the following information to answer the next two exercises. The cost of a leading liquid laundry detergent in different

sizes is given in Table 12.31.

Size (ounces)	Cost ($)	Cost per ounce
16	3.99
32	4.99
64	5.99
200	10.99

Table 12.31

80.

a. Using “size” as the independent variable and “cost” as the dependent variable, draw a scatter plot.

b. Does it appear from inspection that there is a relationship between the variables? Why or why not?

c. Calculate the least-squares line. Put the equation in the form of: y = a + bx

d. Find the correlation coefficient. Is it significant?

e. If the laundry detergent were sold in a 40-ounce size, find the estimated cost.

f. If the laundry detergent were sold in a 90-ounce size, find the estimated cost.

g. Does it appear that a line is the best way to fit the data? Why or why not?

h. Are there any outliers in the given data?

i. Is the least-squares line valid for predicting what a 300-ounce size of the laundry detergent would you cost? Why

or why not?

j. What is the slope of the least-squares (best-fit) line? Interpret the slope.