The reading speed of second grade students in a large city is approximatelynormal, with a mean of 88 words per minute(wpm) and a standard deviation of 10 wpm. Complete parts(a) through(f).

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(a) What is the probability a randomly selected student in the city will read more than 92 words perminute?

The probability is

nothing

.

(Round to four decimal places asneeded.)

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 thispopulation, we would expect

nothing

to read less than 92 words per minute.

B.

If 100 different students were chosen from thispopulation, we would expect

nothing

to read exactly 92 words per minute.

C.

If 100 different students were chosen from thispopulation, we would expect

nothing

to read more than 92 words per minute.

(b) What is the probability that a random sample of 12 second grade students from the city results in a mean reading rate of more than 92 words perminute?

The probability is

nothing

.

(Round to four decimal places asneeded.)

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

A.

If 100 different samples of n=12 students were chosen from thispopulation, we would expect

nothing

sample(s) to have a sample mean reading rate of more than 92 words per minute.

B.

If 100 different samples of n=12 students were chosen from thispopulation, we would expect

nothing

sample(s) to have a sample mean reading rate of exactly 92 words per minute.

C.

If 100 different samples of n=12 students were chosen from thispopulation, we would expect

nothing

sample(s) to have a sample mean reading rate of less than 92 words per minute.

(c) What is the probability that a random sample of 24 second grade students from the city results in a mean reading rate of more than 92 words perminute?

The probability is

nothing

.

(Round to four decimal places asneeded.)

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

A.

If 100 different samples of n=24 students were chosen from thispopulation, we would expect

nothing

sample(s) to have a sample mean reading rate of more than 92 words per minute.

B.

If 100 different samples of n=24 students were chosen from thispopulation, we would expect

nothing

sample(s) to have a sample mean reading rate of less than 92 words per minute.

C.

If 100 different samples of n=24 students were chosen from thispopulation, we would expect

nothing

sample(s) to have a sample mean reading rate of exactly 92 words per minute.

(d) What effect does increasing the sample size have on theprobability? Provide an explanation for this result.

A.

Increasing the sample size decreases the probability because x decreases as n increases.

B.

Increasing the sample size increases the probability because x increases as n increases.

C.

Increasing the sample size decreases the probability because x increases as n increases.

D.

Increasing the sample size increases the probability because x decreases as n increases.

(e) A teacher instituted a new reading program at school. After 10 weeks in theprogram, it was found that the mean reading speed of a random sample of 20 second grade students was 90.4 wpm. What might you conclude based on thisresult? Select the correct choice below and fill in the answer boxes within your choice.

(Type integers or decimals rounded to four decimal places asneeded.)

A.

A mean reading rate of 90.4 wpm is unusual since the probability of obtaining a result of 90.4 wpm or more is

nothing

. This means that we would expect a mean reading rate of 90.4 or higher from a population whose mean reading rate is 88 in

nothing

of every 100 random samples of size n=20 students. The new program is abundantly more effective than the old program.

B.

A mean reading rate of 90.4 wpm is not unusual since the probability of obtaining a result of 90.4 wpm or more is

nothing

. This means that we would expect a mean reading rate of 90.4 or higher from a population whose mean reading rate is 88 in

nothing

of every 100 random samples of size n=20 students. The new program is not abundantly more effective than the old program.

(f) There is a5% chance that the mean reading speed of a random sample of 22 second grade students will exceed whatvalue?

There is a5% chance that the mean reading speed of a random sample of 22 second grade students will exceed

nothing

wpm. (Round to two decimal places asneeded.)

Click to select your answer(s).