Devry MATH221 All Weeks Quizzes Latest 2019 JULY

MATH221 Statistics for Decision Making

Week 3 Quiz

Question 1
(CO 1) Among 500 people at the concert, a survey of 35 found 28% found it too
loud. What is the population and what is the sample?

Population: 500 at that concert; Sample: the
35 in the survey

Population: all concert goers; Sample: the
28% who found it too loud

Population: 500 at that concert: Sample: the
28% who found it too loud

Population: all concert goers; Sample: the
500 at that concert

Question
2(CO 1) A survey of 481 of your customers shows that 79% of them like the
recent changes to the product. Is this percentage a parameter or a statistic
and why?

Parameter as it represents the sample

Statistic as it represents the population

Parameter as it represents the population

Statistic as it represents the sample

Question
3(CO 1) Classify the data of the top grossing movies for 2017.

Statistics

Qualitative

Quantitative

Classical

Question
4(CO 1) The data set that lists the number of performances for each Broadway
show in 2017 would be classified as what type of data?

Ratio

Nominal

Interval

Ordinal

Question
5(CO 1) A data set that includes the number of products that were produced
within each hour by a company would be classified as what type of data?

Ordinal

Ratio

Nominal

Interval

Question
6(CO 1) What type of data collection might be best to estimate the impact of
exercise on longevity?

Simulation

Experiment

Survey

Observational

Question
7(CO 1) What type of data collection might be best to study how voters might
decide an upcoming ballot issue?

Simulation

Survey

Observational

Experiment

Question
8CO 1) You need to study the satisfaction of customers of a specific
restaurant. You decide to randomly select one customer at each table. This
would most closely describe which type of sampling technique?

Stratified

Random

Cluster

Systematic

Question
9(CO 1) Which of the following graphs would be a Pareto chart?

Vertical bars with spaces between with
highest to left and shortest to right

Horizontal bars with various lengths

Vertical base with spaces between of various
heights

Vertical bars with various lengths

Question
10(CO 1) In a normally distributed data set of how long customers stay in your
store, the mean is 31.7 minutes and the standard deviation is 1.9minutes .
Within what range would you expect 95% of your customers to stay in your store?

27.9-35.5

30.75-32.7

29.8-33.6

26.0-37.4

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

MATH221 Statistics for Decision Making

Week 7 Quiz

Question 1(CO
4) From a random sample of 55 businesses, it is found that the mean time that
employees spend on personal issues each week is 4.9 hours with a standard
deviation of 0.35 hours. What is the 95% confidence interval for the amount of
time spent on personal issues?

(4.81, 4.99)

(4.84, 4.96)

(4.83, 4.97)

(4.82, 4.98)

Question 2(CO
4)If a confidence interval is given from 8.50 to 10.25 and the mean is known to
be 9.375, what is the margin of error?

1.750

0.875

8.500

0.438

Question 3(CO
4) If the population standard deviation of a increases without other changes,
what is most likely to happen to the confidence interval?

does not change

widens

cannot determine

narrows

Question 4(CO
4) From a random sample of 41 teens, it is found that on average they spend
43.1 hours each week online with a population standard deviation of 5.91 hours.
What is the 90% confidence interval for the amount of time they spend online
each week?

(37.19, 49.01)

(40.58, 45.62)

(31.28, 54.92)

(41.58, 44.62)

Question 5(CO
4) A company making refrigerators strives for the internal temperature to have
a mean of 37.5 degrees with a population standard deviation of 0.6 degrees,
based on samples of 100. A sample of 100 refrigerators have an average
temperature of 37.48 degrees. Are the refrigerators within the 90% confidence
interval?

Yes, the temperature is within the confidence
interval of (37.40, 37.60)

Yes, the temperature is within the confidence
interval of (36.90, 38.10)

No, the temperature is outside the confidence
interval of (36.90, 38.10)

No, the temperature is outside the confidence
interval of (37.40, 37.60)

Question 6(CO
4) What is the 97% confidence interval for a sample of 104 soda cans that have
a mean amount of 15.10 ounces and a population standard deviation of 0.08
ounces?

(15.940, 15.260)

(15.083, 15.117)

(12.033, 12.067)

(15.020, 15.180)

Question 7(CO
4) Determine the minimum sample size required when you want to be 98% confident
that the sample mean is within two units of the population mean. Assume a
population standard deviation of 5.75 in a normally distributed population.

45

23

43

44

Question 8(CO
4) Determine the minimum sample size required when you want to be 80% confident
that the sample mean is within 1.5 units of the population mean. Assume a
population standard deviation of 9.24 in a normally distributed population.

62

146

145

63

Question 9(CO
4) Determine the minimum sample size required when you want to be 75% confident
that the sample mean is within thirty units of the population mean. Assume a
population standard deviation of 327.8 in a normally distributed population

158

324

197

157

Question 10(CO
4) In a sample of 8 high school students, they spent an average of 28.8 hours
each week doing sports with a sample standard deviation of 3.2 hours. Find the
95% confidence interval, assuming the times are normally distributed.

(25.62, 32.48)

(24.10, 34.50)

(26.12, 31.48)

(22.47, 35.21)