Question

The reading speed of second grade students in a large city is approximately​ normal, with a mean of

9191

words per minute​ (wpm) and a standard deviation of 10 wpm. Complete parts​ (a) through​ (f).

​(a) What is the probability a randomly selected student in the city will read more than

9595

words per​ minute?The probability is

0.34460.3446.

​(Round to four decimal places as​ needed.)

Interpret this probability. Select the correct choice below and fill in the answer box within your choice.

A.If 100 different students were chosen from this​ population, we would expect

nothing

to read less than

9595

words per minute.

B.If 100 different students were chosen from this​ population, we would expect

nothing

to read exactly

9595

words per minute.

C.If 100 different students were chosen from this​ population, we would expect

3434

to read more than

9595

words per minute.Your answer is correct.​(b) What is the probability that a random sample of

1111

second grade students from the city results in a mean reading rate of more than

9595

words per​ minute? The probability is.......

​(Round to four decimal places as​ needed.)

Answer 1

X : The reading speed of second grade students in a large city
µ = mean = 91 words per minute​ (wpm)

σ = standard deviation = =  10 wpm.

​(a) What is the probability a randomly selected student in the city will read more than 95

words per​ minute?

The probability is 0.3446

A.If 100 different students were chosen from this​ population, we would expect 66 to read less than 95 words per minute.

B.If 100 different students were chosen from this​ population, we would expect 0 to read exactly 95 words per minute.

C.If 100 different students were chosen from this​ population, we would expect 34 to read more than 95 words per minute.

(b) What is the probability that a random sample of

11 second grade students from the city results in a mean reading rate of more than 95 words per​ minute?

P( sample mean > 95 ) = P( Z > (95-91)/(10/√11)

= P( z > 1.33 )

= 0.0918

The probability is 0.0918