Question 1

2pts

(CO 4) Consider the following table:

Age GroupFrequency18-2998330-3978440-4968650-5963260-6954170 and over527

If you created the probability distribution for these data, what would be the probability of 40-49?

0.165

0.237

0.425

0.189

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Question 2

2pts

(CO 4) Consider the following table of hours worked by part-time employees. These employees must work in 5 hour blocks.

Weekly hours workedProbability50.06150.18200.61250.15

Find the mean of this variable.

12.20

18.95

2.70

0.61

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Question 3

2pts

(CO 4) Consider the following table:

Defects in batchProbability00.0410.1120.2530.2040.1950.21

Find the variance of this variable.

3.02

2.08

1.41

1.44

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Question 4

2pts

(CO 4) Consider the following table:

Defects in batchProbability00.0410.1120.2530.2040.1950.21

Find the standard deviation of this variable.

1.41

2.08

3.02

1.44

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Question 5

2pts

(CO 4) Forty-nine percent of US teens have heard of a fax machine. You randomly select 12 US teens. Find the probability that the number of these selected teens that have heard of a fax machine is exactly six (first answer listed below). Find the probability that the number is more than 8 (second answer listed below).

0.640, 0.064

0.225, 0.111

0.640, 0.175

0.225, 0.064

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Question 6

2pts

(CO 4) Ten rugby balls are randomly selected from the production line to see if their shape is correct. Over time, the company has found that 85.2% of all their rugby balls have the correct shape. If exactly 7 of the 10 have the right shape, should the company stop the production line?

No, as the probability of seven having the correct shape is unusual

No, as the probability of seven having the correct shape is not unusual

Yes, as the probability of seven having the correct shape is unusual

Yes, as the probability of seven having the correct shape is not unusual

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Question 7

2pts

(CO 4) A bottle of water is supposed to have 12 ounces. The bottling company has determined that 98% of bottles have the correct amount. Which of the following describes a binomial experiment that would determine the probability that a case of 36 bottles has all bottles properly filled?

n=0, p=0.98, x=36

n=36, p=0.98, x=36

n=36, p=0.98, x=12

n=12, p=36, x=98

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Question 8

2pts

(CO 4) On the production line the company finds that 85.6% of products are made correctly. You are responsible for quality control and take batches of 30 products from the line and test them. What number of the 30 being incorrectly made would cause you to shut down production?

Less than 23

Less than 26

Less than 24

Less than 25

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Question 9

2pts

(CO 4) The probability of someone ordering the daily special is 71%. If the restaurant expected 65 people for lunch, how many would you expect to order the daily special?

35

34

46

51

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Question 10

2pts

(CO 4) Seventy-five percent of employees make judgements about their co-workers based on the cleanliness of their desk. You randomly select 8 employees and ask them if they judge co-workers based on this criterion. The random variable is the number of employees who judge their co-workers by cleanliness. Which outcomes of this binomial distribution would be considered unusual?

0, 1, 2, 3, 8

1, 2, 3

0, 1, 2, 7, 8

0, 1, 2, 3

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Question 11

2pts

(CO 4) Seventy-three percent of products come off the line ready to ship to distributors. Your quality control department selects 12 products randomly from the line each hour. Looking at the binomial distribution, if fewer than how many are within specifications would require that the production line be shut down (unusual) and repaired?

Fewer than 10

Fewer than 6

Fewer than 4

Fewer than 5

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Question 12

2pts

(CO 4) Out of each 100 products, 93 are ready for purchase by customers. If you selected 20 products, what would be the expected (mean) number that would be ready for purchase by customers?

19

18

20

93

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Question 13

2pts

(CO 4) Sixty-seven percent of adults have looked at their credit score in the past six months. If you select 29 customers, what is the probability that at least 25 of them have looked at their score in the past six months?

0.005

0.995

0.018

0.013

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Question 14

2pts

(CO 4) One out of every 92 tax returns that a tax auditor examines requires an audit. If 50 returns are selected at random, what is the probability that less than 2 will need an audit?

0.9828

0.8971

0.0109

0.9999

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Question 15

2pts

(CO 4) Thirty-eight percent of consumers prefer to purchase electronics online. You randomly select 16 consumers. Find the probability that the number who prefer to purchase electronics online is at most 3.

0.027

0.912

0.088

0.380

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Question 16

2pts

(CO 5) The speed of cars on a stretch of road is normally distributed with an average 42 miles per hour with a standard deviation of 5.9 miles per hour. What is the probability that a randomly selected car is violating the speed limit of 50 miles per hour?

0.59

0.21

0.09

0.91

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Question 17

2pts

(CO 5) A survey indicates that shoppers spend an average of 22 minutes with a standard deviation of 8 minutes in your store and that these times are normally distributed. Find the probability that a randomly selected shopper will spend less than 20 minutes in the store.

0.22

0.60

0.50

0.40

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Question 18

2pts

(CO 5) The monthly utility bills in a city are normally distributed with a mean of $121 and a standard deviation of $23. Find the probability that a randomly selected utility bill is between $110 and $130.

0.348

0.336

0.190

0.316

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Question 19

2pts

(CO 5) A restaurant serves hot chocolate that has a mean temperature of 175 degrees with a standard deviation of 6.2 degrees. Find the probability that a randomly selected cup of hot chocolate would have a temperature of less than 164 degrees. Would this outcome warrant a replacement cup (meaning that it would be unusual)?

Probability of 0.96 and would warrant a refund

Probability of 0.04 and would not warrant a refund

Probability of 0.04 and would warrant a refund

Probability of 0.96 and would not warrant a refund

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Question 20

2pts

(CO 5) The yearly amounts of carbon emissions from cars in Belgium are normally distributed with a mean of 13.9 gigagrams per year and a standard deviation of 5.8 gigagrams per year. Find the probability that the amount of carbon emissions from cars in Belgium for a randomly selected year are between 11.5 gigagrams and 14.0 gigagrams per year.

0.660

0.397

0.167

0.340

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Question 21

2pts

(CO 5) On average, the parts from a supplier have a mean of 97.5 inches and a standard deviation of 6.1 inches. Find the probability that a randomly selected part from this supplier will have a value between 87.5 and 107.5 inches. Is this consistent with the Empirical Rule of 68%-95%-99.7%?

Probability is 0.05, which is consistent with the Empirical Rule

Probability is 0.95, which is inconsistent with the Empirical Rule

Probability is 0.90, which is consistent with the Empirical Rule

Probability is 0.90, which is inconsistent with the Empirical Rule

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Question 22

2pts

(CO 5) A process is normally distributed with a mean of 104 rotations per minute and a standard deviation of 8.2 rotations per minute. If a randomly selected minute has 80 rotations per minute, would the process be considered in control or out of control?

In control as only one data point would be outside the allowable range

Out of control as this one data point is more than three standard deviations from the mean

In control as this one data point is not more than three standard deviations from the mean

Out of control as this one data point is more than two standard deviations from the mean

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Question 23

2pts

(CO 5) The soup produced by a company has a salt level that is normally distributed with a mean of 5.4 grams and a standard deviation of 0.3 grams. The company takes readings of every 10th bar off the production line. The reading points are 5.8, 5.9, 4.9, 6.5, 5.0, 4.9, 6.2, 5.1, 5.7, 6.1. Is the process in control or out of control and why?

It is out of control as one of these data points is more than 3 standard deviations from the mean

It is in control as the data points more than 2 standard deviations from the mean are far apart

It is out of control as two of these data points are more than 2 standard deviations from the mean

It is in control as the values jump above and below the mean

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Question 24

2pts

(CO 5) The blenders produced by a company have a normally distributed life span with a mean of 8.2 years and a standard deviation of 1.3 years. What warranty should be provided so that the company is replacing at most 6% of their blenders sold?

6.9 years

6.2 years

10.2 years

9.5 years

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Question 25

2pts

(CO 5) A puck company wants to sponsor the players with the 10% quickest goals in hockey games. The times of first goals are normally distributed with a mean of 12.56 minutes and a standard deviation of 4.91 minutes. How fast would a player need to make a goal to be sponsored by the puck company?

7.65 minutes

18.85 minutes

17.47 minutes

6.27 minutes

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Question 26

2pts

(CO 5) A stock's price fluctuations are approximately normally distributed with a mean of $104.50 and a standard deviation of $23.62. You decide to purchase whenever the price reaches its lowest 15% of values. What is the most you would be willing to pay for the stock?

$80.88

$80.02

$84.62

$128.98

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Question 27

2pts

(CO 5) The times that customers spend in a book store are normally distributed with a mean of 39.5 minutes and a standard deviation of 15.9 minutes. A random sample of 60 customers has a mean of 36.1 minutes or less. Would this outcome be considered unusual, so that the store should reconsider its displays?

No, the probability of this outcome at 0.049, would be considered usual, so there is no problem

Yes, the probability of this outcome at 0.049, would be considered unusual, so the display should be redone

No the probability of this outcome at 0.415 would be considered usual, so there is no problem

Yes, the probability of this outcome at 0.951 would be considered unusual, so the display should be redone

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Question 28

2pts

(CO 5) The weights of ice cream cartons are normally distributed with a mean weight of 20 ounces and a standard deviation of 0.3 ounces. You randomly select 25 cartons. What is the probability that their mean weight is greater than 20.06 ounces?

0.159

0.579

0.841

0.421

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Question 29

2pts

(CO 5) Recent test scores on the Law School Admission Test (LSAT) are normally distributed with a mean of 162.4 and a standard deviation of 15.9. What is the probability that the mean of 8 randomly selected scores is less than 160?

0.665

0.335

0.560

0.440

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Question 30

2pts

(CO 5) The mean annual salary for intermediate level executives is about $74000 per year with a standard deviation of $2500. A random sample of 36 intermediate level executives is selected. What is the probability that the mean annual salary of the sample is between $71000 and $73500?

0.306

0.008

0.076

0.115