The standard deviation alone does not measure relative variation. For example, a standard deviation of $1 would be considered large if it is describing the variability from store to store in the price of an ice cube tray. On the other hand, a standard deviation of $1 would be considered small if it is describing store-to-store variability in the price of a particular brand of freezer.

A quantity designed to give a relative measure of variability is the coefficient of variation. Denoted by CV, the coefficient of variation expresses the standard deviation as a percentage of the mean. It is defined by the following formula.

CV = 100(s/x)

Consider two samples. Sample 1 gives the actual weight (in ounces) of the contents of cans of pet food labeled as having a net weight of 8 ounces. Sample 2 gives the actual weight (in pounds) of the contents of bags of dry pet food labeled as having a net weight of 50 pounds. The weights for the two samples are as follows.

Sample 1	9.6	8.2	8.8	9.6	8.8
9.6	9.9	8.1	8.1	8.8
Sample 2	51.0	51.2	51.1	52.4	51.7
47.0	50.4	50.3	48.7	48.2

(a)

For each of the given samples, calculate the mean and the standard deviation. (Round your standard deviations to four decimal places.)

Sample 1

MeanStandard Deviation

Sample 2

MeanStandard Deviation

(b)

Calculate the coefficient of variation for each sample. (Round your answers to two decimal places.)

CV₁CV₂