Question 1
pts
The length of time a person takes to decide which shoes to purchase is normally distributed with a
mean of 8.21 minutes and a standard deviation of 1.90. Find the probability that a randomly selected
individual will take less than 5 minutes to select a shoe purchase. Is this outcome unusual?
You Answered
Probability is 0.954, which is unusual as it is greater than 5%
Probability is 0.045, which is usual as it is not less than 5%
Correct Answer
Probability is 0.045, which is unusual as it is less than 5%
Probability is 0.954, which is usual as it is greater than 5%
Question 2
pts
Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. Find the
probability that a randomly selected bill will have an amount greater than $165, which the city
believes might indicate that someone is wasting water. Would a bill that size be considered unusual?
Probability is 0.04, which is usual as it is less than 5%
Probability is 0.96, which is usual as it is greater than 5%
Correct!
Probability is 0.04, which is unusual as it is less than 5%
Probability is 0.96, which is unusual as it is greater than 5%
,Question 3
pts
In a health club, research shows that on average, patrons spend an average of 42.5 minutes on the
treadmill, with a standard deviation of 4.8 minutes. It is assumed that this is a normally distributed
variable. Find the probability that randomly selected individual would spent between 35 and 48
minutes on the treadmill.
-0.19
Correct!
0.81
0.19
0.62
Question 4
pts
A tire company measures the tread on newly-produced tires and finds that they are normally
distributed with a mean depth of 0.99mm and a standard deviation of 0.35mm. Find the probability
that a randomly selected tire will have a depth less than 0.31mm. Would this outcome warrant a
refund (meaning that it would be unusual)?
You Answered
Probability of 0.97 and would warrant a refund
Probability of 0.97 and would not warrant a refund
Probability of 0.03 and would not warrant a refund
Correct Answer
,Probability of 0.03 and would warrant a refund
Question 5
pts
A grocery stores studies how long it takes customers to get through the speed check lane. They
assume that if it takes more than 10 minutes, the customer will be upset. Find the probability that a
randomly selected customer takes more than 10 minutes if the average is 7.45 minutes with a
standard deviation of 1.04 minutes.
0.501
0.993
Correct Answer
0.007
You Answered
0.071
Question 6
pts
In an agricultural study, the average amount of corn yield is normally distributed with a mean of 185.2
bushels of corn per acre, with a standard deviation of 23.5 bushels of corn. If a study included 1200
acres, about how many would be expected to yield more than 190 bushels of corn per acre?
Correct Answer
503 acres
You Answered
282 acres
, 419 acres
581 acres
Question 7
pts
On average, the parts from a supplier have a mean of 35.8 inches and a standard deviation of 2.4
inches. Find the probability that a randomly selected part from this supplier will have a value between
28.6 and 43.0 inches. Is this consistent with the Empirical Rule of 68%-95%-99.7%?
Probability is 0.05, which is inconsistent with the Empirical Rule
Probability is 0.95, which is inconsistent with the Empirical Rule
Probability is 0.997, which is inconsistent with the Empirical Rule
Correct!
Probability is 0.997, which is consistent with the Empirical Rule
Question 8
pts
A process is normally distributed with a mean of 10.2 hits per minute and a standard deviation of 1.04
hits. If a randomly selected minute has 13.9 hits, would the process be considered in control or out of
control?
You Answered
In control as only one data point would be outside the allowable range
Correct Answer
Out of control as this one data point is more than three standard deviations from the mean
pts
The length of time a person takes to decide which shoes to purchase is normally distributed with a
mean of 8.21 minutes and a standard deviation of 1.90. Find the probability that a randomly selected
individual will take less than 5 minutes to select a shoe purchase. Is this outcome unusual?
You Answered
Probability is 0.954, which is unusual as it is greater than 5%
Probability is 0.045, which is usual as it is not less than 5%
Correct Answer
Probability is 0.045, which is unusual as it is less than 5%
Probability is 0.954, which is usual as it is greater than 5%
Question 2
pts
Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. Find the
probability that a randomly selected bill will have an amount greater than $165, which the city
believes might indicate that someone is wasting water. Would a bill that size be considered unusual?
Probability is 0.04, which is usual as it is less than 5%
Probability is 0.96, which is usual as it is greater than 5%
Correct!
Probability is 0.04, which is unusual as it is less than 5%
Probability is 0.96, which is unusual as it is greater than 5%
,Question 3
pts
In a health club, research shows that on average, patrons spend an average of 42.5 minutes on the
treadmill, with a standard deviation of 4.8 minutes. It is assumed that this is a normally distributed
variable. Find the probability that randomly selected individual would spent between 35 and 48
minutes on the treadmill.
-0.19
Correct!
0.81
0.19
0.62
Question 4
pts
A tire company measures the tread on newly-produced tires and finds that they are normally
distributed with a mean depth of 0.99mm and a standard deviation of 0.35mm. Find the probability
that a randomly selected tire will have a depth less than 0.31mm. Would this outcome warrant a
refund (meaning that it would be unusual)?
You Answered
Probability of 0.97 and would warrant a refund
Probability of 0.97 and would not warrant a refund
Probability of 0.03 and would not warrant a refund
Correct Answer
,Probability of 0.03 and would warrant a refund
Question 5
pts
A grocery stores studies how long it takes customers to get through the speed check lane. They
assume that if it takes more than 10 minutes, the customer will be upset. Find the probability that a
randomly selected customer takes more than 10 minutes if the average is 7.45 minutes with a
standard deviation of 1.04 minutes.
0.501
0.993
Correct Answer
0.007
You Answered
0.071
Question 6
pts
In an agricultural study, the average amount of corn yield is normally distributed with a mean of 185.2
bushels of corn per acre, with a standard deviation of 23.5 bushels of corn. If a study included 1200
acres, about how many would be expected to yield more than 190 bushels of corn per acre?
Correct Answer
503 acres
You Answered
282 acres
, 419 acres
581 acres
Question 7
pts
On average, the parts from a supplier have a mean of 35.8 inches and a standard deviation of 2.4
inches. Find the probability that a randomly selected part from this supplier will have a value between
28.6 and 43.0 inches. Is this consistent with the Empirical Rule of 68%-95%-99.7%?
Probability is 0.05, which is inconsistent with the Empirical Rule
Probability is 0.95, which is inconsistent with the Empirical Rule
Probability is 0.997, which is inconsistent with the Empirical Rule
Correct!
Probability is 0.997, which is consistent with the Empirical Rule
Question 8
pts
A process is normally distributed with a mean of 10.2 hits per minute and a standard deviation of 1.04
hits. If a randomly selected minute has 13.9 hits, would the process be considered in control or out of
control?
You Answered
In control as only one data point would be outside the allowable range
Correct Answer
Out of control as this one data point is more than three standard deviations from the mean
