Devry MATH221 Week 5 Quiz Latest 2020 April

MATH221 Statistics for Decision Making

Week 5 Quiz   

Question 1 (CO 3) Consider the following table:

Age Group          Frequency

18-29     983

30-39     784

40-49     686

50-59     632

60-69     541

70 and over        527

If you created the probability distribution for these data, what would be the probability of 30-39?

  0.425

  0.237

Correct!

  0.189

  0.165

Question 2 (CO 3) Consider the following table of hours worked by part-time employees. These employees must work in 5 hour blocks.

Weekly hours worked   Probability

5              0.15

15           0.28

20           0.31

25           0.26

Find the mean of this variable.

  17.50

  20.60

  17.65

  18.95

Question 3 (CO 3) Consider the following table:

Defects in batch               Probability

0              0.21

1              0.28

2              0.30

3              0.09

4              0.08

5              0.04

Find the variance of this variable.

  1.67

  1.78

  1.99

  1.33

Question 4 (CO 3) Consider the following table:

Defects in batch               Probability

0              0.21

1              0.28

2              0.30

3              0.09

4              0.08

5              0.04

Find the standard deviation of this variable.

  1.41

  1.67

  1.33

  1.78

Question 5 (CO 3) Twenty-two 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).

  0.993, 0.024

  0.024, 0.001

  0.993, 0.000

  0.024, 0.000

Question 6(CO 3) Ten rugby balls are randomly selected from the production line to see if their shape is correct. Over time, the company has found that 92.4% 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

Question 7 (CO 3) A bottle of water is supposed to have 20 ounces. The bottling company has determined that 96% 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=36, x=98

  n=36, p=0.98, x=1

  n=20, p=0.98, x=36

  n=36, p=0.96, x=36

Question 8 (CO 3) On the production line the company finds that 90.2% 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 26

  Less than 25

  Less than 28

  Less than 24

Question 9 (CO 3) The probability of someone ordering the daily special is 52%. If the restaurant expected 105 people for lunch, how many would you expect to order the daily special?

  51

  55

  100

  52

Question 10 (CO 3) 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?

  1, 2, 3

  0, 1, 2, 7, 8

  0, 1, 2, 3, 8

  0, 1, 2, 3