Question

The reading speed of second grade students is approximately normal, with a mean of 91 words per minute (wpm) and a standard deviation of 11.

A) What is the probability that a single randomly selected student will read more than 97 words per minute?

B) What is the probability that a random sample of 12 students will have a mean reading rate of more than 97 words per minute?

C) There is a 5% chance that the mean reading speed of a random sample of 97 second grade students will exceed what value? (Round to the nearest integer)

Answer 1

A)

The following information has been provided:

We need to compute . The corresponding z-value needed to be computed is:

Therefore, we get that

B)

The following information about the mean and standard deviation has been provided:

We need to compute . The corresponding z-value needed to be computed is:

Therefore, we get that

C)

We need to find

Also, P[ Z > 1.645 ] = 0.05

Comparing

x = 91 + 1.84

x = 92.84