Devry MATH221 Week 5 Quiz Latest 2019 JULY Question # 00603525 Course Code : MATH221 Subject: Mathematics Due on: 08/08/2019 Posted On: 08/08/2019 11:17 AM Tutorials: 1 Rating: 4.5/5

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?

0.165

0.237

0.425

0.189

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 0.06

15 0.61

20 0.18

25 0.15

Find the
mean of this variable.

12.20

17.50

18.95

16.80

Question 3(CO 3) Consider the following table.

Defects in
batch Probability

0 0.30

1 0.28

2 0.21

3 0.09

4 0.08

5 0.04

Find the
variance of this variable.

1.49

0.67

1.41

1.99

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.

1.33

1.67

1.78

1.41

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).

0.024, 0.001

0.993, 0.000

0.993, 0.024

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 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?

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

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

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

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

Question 7(CO 3) 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=12, p=36, x=98

n=36, p=0.98, x=36

n=36, p=0.98, x=12

n=0, p=0.98, x=36

Question 8(CO 3) On the production line the
company finds that 95.6% 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 26

Less than 28

Less than 27

More than 25

Question 9(CO 3) The probability of someone
ordering the daily special is 52%. If the restaurant expected 65 people for
lunch, how many would you expect to order the daily special?

34

35

30

31

Question 10(CO 3) Fifty-seven 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, 8

1, 2, 8

1, 2, 8

0, 1, 2, 8

Question 11(CO 3) 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 6

Fewer than 4

Fewer than 5

Fewer than 10

Question 12(CO 3) Out of each 100 products, 96
are ready for purchase by customers. If you selected 27 products, what would be
the expected (mean) number that would be ready for purchase by customers?

27

0.96

26

96

Question 13(CO 3) Sixty-seven percent of
adults have looked at their credit score in the past six months. If you select
31 customers, what is the probability that at least 20 of them have looked at
their score in the past six months?

0.450

0.550

0.142

0.692

Question 14(CO 3) 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 3 will need an
audit?

0.9978

0.0109

0.9828

0.0151

Question 15(CO 3) 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 5.

0.211

0.789

0.180

0.391

Question 16 (CO 3) The speed of cars on a
stretch of road is normally distributed with an average 51 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?

0.50

0.43

0.51

0.57

Question 17(CO
3) A survey indicates that shoppers spend an average of 22 minutes with a
standard deviation of 16 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.

0.20

0.37

0.45

0.55

Question 18(CO
3) The monthly utility bills in a city are normally distributed with a mean of
$128 and a standard deviation of $23. Find the probability that a randomly
selected utility bill is between $110 and $130.

0.318

0.316

0.783

0.217

Question 19(CO 3) A restaurant serves hot
chocolate that has a mean temperature of 175 degrees with a standard deviation
of 8.1 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 0.09 and would not warrant a
refund

Probability of 0.91 and would not warrant a
refund

Probability of 0.09 and would warrant a
refund

Probability of 0.91 and would warrant a
refund

Question 20(CO 3) 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 9.2 gigagrams per year. Find the
probability that the amount of carbon emissions from cars in Belgium for a
randomly selected year are between 12.8 gigagrams and 14.0 gigagrams per year.

0.519

0.052

0.452

0.548

Question 21(CO 3) On average, the parts from a
supplier have a mean of 97.5 inches and a standard deviation of 12.2 inches.
Find the probability that a randomly selected part from this supplier will have
a value between 85.3 and 109.7 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 0.68, which is consistent with
the Empirical Rule

Probability is 0.95, which is consistent with
the Empirical Rule

Probability is 0.68, which is inconsistent with
the Empirical Rule

Question 22(CO 3) 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?

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

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

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

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

Question 23 (CO 3) 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, 5.2, 5.0,
4.9, 6.2, 5.1, 6.7, 6.1. Is the process in control or out of control and why?

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

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

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

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

Question 24(CO
3) 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

9.5 years

6.2 years

10.2 years

Question 25(CO 3) 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 8.54 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?

14.83 minutes

7.92 minutes

9.16 minutes

2.25 minutes

Question 26(CO 3) 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 20% of values. What is the most you would be willing to pay for the
stock?

$124.38

$98.52

$110.48

$84.62

Question 27(CO 3) The times that customers
spend in a book store are normally distributed with a mean of 39.5 minutes and
a standard deviation of 9.4 minutes. A random sample of 25 customers has a mean
of 36.1 minutes or less. Would this outcome be considered unusual, so that the
store should reconsider its displays?

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

No the probability of this outcome at 0.359
would be considered usual, so there is no problem

Yes, the probability of this outcome at 0.965
would be considered unusual, so the display should be redone

No, the probability of this outcome at 0.035,
would be considered usual, so there is no problem

Question 28(CO 3) The weights of ice cream
cartons are normally distributed with a mean weight of 20 ounces and a standard
deviation of 0.5 ounces. You randomly select 25 cartons. What is the probability
that their mean weight is greater than 20.06 ounces?

0.274

0.726

0.452

0.548

Question 29(CO 3) 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 12
randomly selected scores is less than 161?

0.465

0.380

0.620

0.535

Question 30(CO 3) The mean annual salary for
intermediate level executives is about $74000 per year with a standard
deviation of $2000. 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?

0.334

0.067

0.933

0.885