Question

The physics scores of 200 students follow a normal distribution with a mean of 75 and standard deviation of 7. Which conclusion is best supported by this information?

A. About 32 students have a score higher than 89.
B. About 5 students have a score higher than 89.
C. About 100 students have a score higher than 89.
D. About 4 students have a score lower than 89.
E. About 32 students have a score lower than 89.

Answer 1

the correct answer is A cuz the score has 2 be higher than 89

Answer 2

About 5 students have a score higher than 89.

Explanation:

Given : The physics scores of 200 students follow a normal distribution with a mean of 75 and standard deviation of 7.

To Find: Which conclusion is best supported by this information?

Solution:

Mean =
`\mu=7`

Standard deviation =
`\sigma = 7`

n = 200

Formula :
`z = (x-\mu)/(\sigma)`

Substitute the values.

`z = (89-75)/(7)`

`z = 2`

So, P(z<2)=0.9772

So, P(z<89)=
`200 * 0.9772=195.44`

So, 195 students have score less than 89

So, Remaining 5 students have score higher than 89.

So, Option B is true.

Hence About 5 students have a score higher than 89.