Question 1 of 36
A sample of size will be drawn from a population with mean and standard deviation . Use the
Cumulative Normal Distribution Table if needed.
(a) Find the probability that will be less than . Round the final answer to at least four decimal
places.
(b) Find the percentile of . Round the answer to at least two decimal places.
Part 1 of 2
Find the probability that will be less than . Round the final answer to at least four decimal
places.

Find the percentile of . Round the answer to at least two decimal places.
Question 2 of 36
A sample of size will be drawn from a population with mean and standard deviation . Use the
Cumulative Normal Distribution Table if needed.
(a) Find the probability that will be less than . Round the final answer to at least four decimal
places.
(b) Find the percentile of . Round the answer to at least two decimal places.
80 81 22
x 86
85
th x
x
86
The probability that x will be less than 86 is .
85th x
The 85th percentile of x is .
50 72 20
x 73
55
th x

Find the probability that will be less than . Round the final answer to at least four decimal
places.
Part 2 of 2
Find the percentile of . Round the answer to at least two decimal places.
Question 3 of 36
A sample of size will be drawn from a population with mean and standard deviation . Use the
Cumulative Normal Distribution Table if needed.
(a) Find the probability that will be between and . Round the final answer to at least four
decimal places.
(b) Find the percentile of . Round the answer to at least two decimal places.
Part 1 of 2
Find the probability that will be between and . Round the final answer to at least four
decimal places.
Part 2 of 2
Find the percentile of . Round the answer to at least two decimal places.
x 73
The probability that x will be less than 73 is .
55th x
The 55th percentile of x is .
105 15 6
x 14 16
55
th x
x
14 16
The probability that x will be between 14 and 16 is .
55th x
The 55th percentile of x is .

Question 4 of 36
Watch your cholesterol: The mean serum cholesterol level for U.S. adults was , with a standard
deviation of (the units are milligrams per deciliter). A simple random sample of adults is chosen.
Use the Cumulative Normal Distribution Table if needed. Round the answers to at least four decimal
places.
(a) What is the probability that the sample mean cholesterol level is greater than ?
(b) What is the probability that the sample mean cholesterol level is between and ?
(c) Would it be unusual for the sample mean to be less than ?
Part 1 of 3
What is the probability that the sample mean cholesterol level is greater than ?
Part 2 of 3
What is the probability that the sample mean cholesterol level is between and ?
Part 3 of 3
Would it be unusual for the sample mean to be less than ?
202
41 110
210
190 200
198
210
The probability that the sample mean cholesterol level is greater than 210 is .
190 200
The probability that the sample mean cholesterol level is between 190 and 200 is .
198
It be unusual for the sample mean to be less than , since the probability is
.
(Choose one)
198

Question 5 of 36
Taxes: The Internal Revenue Service reports that the mean federal income tax paid in the year
was . Assume that the standard deviation is . The IRS plans to draw a sample of tax
returns to study the effect of a new tax law.
(a) What is the probability that the sample mean tax is less than ?
(b) What is the probability that the sample mean tax is between and ?
(c) Find the percentile of the sample mean.
(d) Would it be unusual if the sample mean were less than ?
(e) Do you think it would be unusual for an individual to pay a tax of less than ? Explain.
Part 1 of 5
(a) What is the probability that the sample mean tax is less than ? Round the answer to at
least four decimal places.
Part 2 of 5
(b) What is the probability that the sample mean tax is between and ? Round the
answer to at least four decimal places.
Part 3 of 5
(c) Find the percentile of the sample mean. Round the answer to at least one decimal place.
2010
$8040 $4700 1000
$8100
$7600 $8000
10
th
$7600
$7600
$8100
The probability that the sample mean tax is less than $8100 is .
$7600 $8000
The probability that the sample mean tax is between $7600 and $8000 is .
10th
The 10th percentile of the sample mean is $ .

Part 4 of 5
(d) Would it be unusual if the sample mean were less than ? Round the answer to at least
four decimal places.
Part 5 of 5
(e) Do you think it would be unusual for an individual to pay a tax of less than ? Explain.
Assume the population is approximately normal. Round the answer to at least four decimal places.
Question 6 of 36
High-rent district: The mean monthly rent for a one-bedroom apartment without a doorman in
Manhattan is . Assume the standard deviation is . A real estate firm samples apartments.
Use the Cumulative Normal Distribution Table if needed.
(a) What is the probability that the sample mean rent is greater than ?
(b) What is the probability that the sample mean rent is between and ?
(c) Find the percentile of the sample mean.
(d) Would it be unusual if the sample mean were greater than ?
(e) Do you think it would be unusual for an individual apartment to have a rent greater than ?
Explain. Assume the population is approximately normal.
Part 1 of 5
(a) What is the probability that the sample mean rent is greater than ? Round the answer to
at least four decimal places.
$7600
It unusual because the probability of the sample mean being less than is
.
(Choose one)
$7600
$7600
It be unusual for an individual to pay a tax of less than , since the
probability is .
(Choose one)
$7600
$2550 $485 85
$2620
$2419 $2519
60
th
$2700
$2700
$2620
The probability that the sample mean rent is greater than $2620

Probability