The number of books borrowed from a library each week follows a normal distribution. When a sample is taken for several weeks, t

Question

2 years ago

12

The number of books borrowed from a library each week follows a normal distribution. When a sample is taken for several weeks, t

he mean is found to be 190 and the standard deviation is 30. What is the percentage of the chance that more than 250 books were borrowed in a week?
a. 99.7
b. 95
c. 13.5
d. 2.5

Mathematics

2 answers:

MissTica · Answer 1 · 2022-05-04T00:03:41+03:00

MissTica2 years ago

6 0

Answer:

D. 2.5

Step-by-step explanation:

For all Plato users

12345 [234] · Answer 2 · 2022-05-03T22:42:54+03:00

1 SD away from mean is 68% of data.
2 SD away from mean is 95% of data.
3 SD away from mean is 99.7% of data.

1 SD away:
190+30=220

2 SD away:
220+30=250

This shows we are on the outer 5 percent of the normal distribution.
Since you said "more", that means we only look at the right side of your 5%, which is only 2.5%

answer is D, 2.5%