Quinn mailed four postcards that each cost $0.25, five letters that each cost $0.44, two large envelopes that each cost $0.80, and one small package for $5.10. which cost on the list of mailing fees on quinn’s receipt would skew the mean? a. the cost of a postcardb. the cost of a letterc. the cost of a large enveloped. the cost of the small package

The correct answer is:

D) the cost of the small package.

Explanation:

The mean of a data set is found by adding together all of the data values and dividing by the number of data values.

Most of the prices on this list are near one another.  The three smallest prices are $0.25, $0.44, and $0.80; all are less than $1.  The largest price, however, is more than 5 times that amount.

The effect of this largest value are that it nearly doubles the mean.

The mean of the data set including the largest value is:
[4(0.25)+5(0.44)+2(0.80)+1(5.10)]/12 = 9.90/12 = 0.825

The mean of the data set without the largest value is:
[4(0.25)+5(0.44)+2(0.80)]/11 = 4.80/11 = 0.436

The right answer to this question is D - the cost of the small package. We can work this out because the cost of the small package is so much greater than everything else, and therefore acts as the outlier that will skew the mean.