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.

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

1 the 1st term, 3 the 2nd term, 6 the 3rd term,etc.

note the following:

from the 1st term (1) to the 2nd term (3), we go up by 2,from the 2nd term (3) to the 3rd term (6), we go up by 3from the 3rd term (6) to the 4th term (10), we go up by 4, andfrom the 4th term (10) to the 5th term (15), we go up by 5.

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for