Answer:
Affects the width of a confidence interval, as the margin of error is a function of the sample standard deviation.
Step-by-step explanation:
When we have the standard deviation for the sample, the t-distribution is used to solve the question.
It does not affect the center of the interval, which is a function only of the sample mean.
Width of a confidence interval:
The width of a confidence interval is a function of the margin of error, which is:

In which s is related to the sample standard deviation. Thus, since s and M are directly proportional, a higher standard deviation makes the interval wider, lower standard deviation makes the interval narrower, and thus, the sample standard deviation affects the the width of a confidence interval.
The answer would be about 66. Ps . I hate that website. It's for common core learingl it is soooo boring !
N+7 - 7 more songs added
n-2 - 2 songs deleted (subtracted)
4n - 4 times more songs than before
n/2 - the number of songs cut in half (divided by 2)
First multiply 20% by 50: .2x50=10. Then subtract that from 50: 50-10=40. The new price is $40 :)