Question

Question 1 2 pts

Let x represent the height of first graders in a class. This would be considered what type of variable:

Nonsensical

Lagging

Continuous

Discrete

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Question 2 2 pts

Let x represent the height of corn in Oklahoma. This would be considered what type of variable:

Discrete

Inferential

Distributed

Continuous

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Question 3 2 pts

Consider the following table.

Age Group	Frequency
18-29	9831
30-39	7845
40-49	6869
50-59	6323
60-69	5410
70 and over	5279

If you created the probability distribution for these data, what would be the probability of 18-29?

23.7%

16.5%

18.9%

42.5%

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Question 4 2 pts

Consider the following table.

Weekly hours worked	Probability
1-30 (average=22)	0.08
31-40 (average=35)	0.41
41-50 (average=46)	0.47
51 and over (average=61)	0.04

Find the mean of this variable.

35.9

39.0

41.0

40.2

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Question 5 2 pts

Consider the following table.

Defects in batch	Probability
0	0.28
1	0.35
2	0.16
3	0.09
4	0.10
5	0.02

Find the variance of this variable.

1.35

1.83

0.85

1.44

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Question 6 2 pts

Consider the following table.

Defects in batch	Probability
2	0.15
3	0.44
4	0.18
5	0.10
6	0.07
7	0.06

Find the standard deviation of this variable.

1.36

0.93

1.86

3.68

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Question 7 2 pts

The standard deviation of samples from supplier A is 0.4582, while the standard deviation of samples from supplier B is 0.3358. Which supplier would you be likely to choose based on these data and why?

Supplier B, as their standard deviation is higher and, thus, easier to fit into our production line

Supplier A, as their standard deviation is lower and, thus, easier to fit into our production line

supplier B, as their standard deviation is lower and, thus, easier to fit into our production line

Supplier A, as their standard deviation is higher and, thus easier to fit into our production line

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Question 8 2 pts

Thirty-five percent of teens buy soda (pop) at least once each week. Eleven kids are randomly selected. The random variable represents the number of these kids who purchase soda (pop) at least once each week. For this to be a binomial experiment, what assumption needs to be made?

All teens have the same probability of being selected

The probability of being a teen and being a kid should be the same

All the kids eligible to be selected are teens

All eleven kids selected live in the same region

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Question 9 2 pts

A survey found that 39% of all gamers play video games on their smartphones. Ten frequent gamers are randomly selected. The random variable represents the number of frequent games who play video games on their smartphones. What is the value of p?

x, the counter

0.10

10

0.39

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Question 10 2 pts

Thirty-five percent of US adults have little confidence in their cars. You randomly select ten US adults. Find the probability that the number of US adults who have little confidence in their cars is (1) exactly six and then find the probability that it is (2) more than 7.

(1) 0.069 (2) 0.974

(1) 0.021 (2) 0.026

(1) 0.069 (2) 0.005

(1) 0.021 (2) 0.005

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Question 11 2 pts

Say a business found that 29.5% of customers in Washington prefer grey suits. The company chooses 8 customers in Washington and asks them if they prefer grey suits. What assumption must be made for this study to follow the probabilities of a binomial experiment?

That the probability of being a selected customer is the same for all 8 people

That those selected have similar characteristics to those in the original study

That there is a 29.3% probability of being a selected customer

That the probability of preferring grey suites is the same as preferring suits of other colors

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Question 12 2 pts

Seven baseballs are randomly selected from the production line to see if their stitching is straight. Over time, the company has found that 89.4% of all their baseballs have straight stitching. If exactly five of the seven have straight stitching, should the company stop the production line?

Yes, the probability of exactly five having straight stitching is unusual

No, the probability of exactly five have straight stitching is not unusual

No, the probability of five or less having straight stitching is not unusual

Yes, the probability of five or less having straight stitching is unusual

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Question 13 2 pts

A beer company puts 15 ounces of beer in each can. The company has determined that 95.5% of cans have the correct amount. Which of the following describes a binomial experiment that would determine the probability that a case of 16 cans has all cans that are properly filled?

n=16, p=0.95, x=1

n=16, p=0.955, x=16

n=15, p=0.95, x=16

n=15, p=0.955, x=15

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Question 14 2 pts

A supplier must create metal rods that are 18.1 inches long to fit into the next step of production. Can a binomial experiment be used to determine the probability that the rods are correct length or an incorrect length?

No, as there are three possible outcomes, rather than two possible outcomes

Yes, as each rod measured would have two outcomes: correct or incorrect

No, as the probability of being about right could be different for each rod selected

Yes, all production line quality questions are answered with binomial experiments

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Question 15 2 pts

In a box of 12 pens, there is one that does not work. Employees take pens as needed. The pens are returned once employees are done with them. You are the 5^th employee to take a pen. Is this a binomial experiment?

No, binomial does not include systematic selection such as “fifth”

Yes, with replacement, the probability of getting the one that does not work is the same

No, the probability of getting the broken pen changes as there is no replacement

Yes, you are finding the probability of exactly 5 not being broken

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Question 16 2 pts

Forty-two percent of employees make judgements about their co-workers based on the cleanliness of their desk. You randomly select 7 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?

1, 6, 7

0, 1, 2, 7

0, 1, 7

1, 2, 6, 7

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Question 17 2 pts

Sixty-eight percent of products come off the line within product specifications. Your quality control department selects 15 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 8

Fewer than 9

Fewer than 11

Fewer than 10

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Question 18 2 pts

The probability of a potential employee passing a drug test is 86%. If you selected 15 potential employees and gave them a drug test, how many would you expect to pass the test?

12 employees

13 employees

15 employees

14 employees

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Question 19 2 pts

The probability of a potential employee passing a training course is 86%. If you selected 15 potential employees and gave them the training course, what is the probability that more than 12 will pass the test?

0.648

0.352

0.900

0.852

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Question 20 2 pts

Off the production line, there is a 3.7% chance that a candle is defective. If the company selected 45 candles off the line, what is the probability that fewer than 3 would be defective?

0.975

0.916

0.037

0.768

Answer 1

1. Option C. Since height can take any value.

2. Option D. Continuous. Similar reason as answer 1

3. Option A. 23.7%. Probability=relative frequency = frequncy of class 18-29/total frequency

4. Option D. 40.2. mean= sum(probability*value)

5. Option C. 1.86. Find E(X), Then E(X^2). Then E(x^2)-E(X)^2

6. Option A. 1.36. SD(x)=Sqrt(Var(X). Same procedure as question 5

7. Option C.supplier B, as their standard deviation is lower and, thus, easier to fit into our production line

8. Option A.All teens have the same probability of being selected

9. Option D. 0.39. Since 39% of games play on their smartphone