# MATH221 Week 3 Quiz (July 2019)

**MATH 221 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

Question 11(CO 1) Which of the following graphs would be considered a uniform distribution?

Vertical bars that are all the same height

Vertical bars that are short on the left, increase to the tallest in the middle and then become shorter to the right

Vertical bars with tallest on left down to shortest on right

Vertical bars with shortest on left up to tallest on right

Question 12(CO 1) In a normally distributed data set with a mean of 22 and a standard deviation of 4.1, what percentage of the data would be between 13.8 and 30.2?

68% based on the histogram

95% based on the Empirical Rule

68% based on the Empirical Rule

95% based on the histogram

Question 13(CO 1) Which of the following would be the standard deviation for this sample data set: 5, 7, 3, 9, 2, 4, 4, 6, 5, 9, 3?

5.18

2.59

2.36

2.25

Question 14(CO 1) What would be the mean of this data set: 8, 9, 7, 508, 7, 1, 5, 3, 4?

61.3

5.7

57.0

55.2

Question 15

(CO 1) A pharmaceutical company wants to determine if its new medicine helps heal bruises more quickly than not treating the bruise. What type of study would be best suited to make this determination?

Survey

Experimental

Simulation

Observational

Question 16(CO 1) To gather information on customer satisfaction, a researcher goes into the local store and interviews six randomly selected customers. This sampling technique is called:

Convenience

Random

Cluster

Stratified

Question 17(CO 1) What is the standard deviation and its meaning in the sample of customer ages? 45, 76, 30, 22, 51, 40, 63, 66, 27

17.8 which means that many of the ages will be around this value

18.8 which means that many of the ages will be around the square of this value

18.8 which means that many of the ages will be within this value of the average age

17.8 which means that many of the ages will be within half of this value of the average age

Question 18(CO 2) A random selection from a deck of cards selects one card. What is the probability of selecting an ace?

0.50

0.025

0.077

0.250

Question 19(CO 2) What is the sample space of flipping three coins, where H=heads, and T=tails?

(H,H,T)(H,T,T)(T,H,H)(T,T,H)(T,T,T)(T,H,T)(H,T,H)

(H,H,H)(H,H,T)(H,T,T)(T,H,H)(T,T,H)(T,T,T)(T,H,T)(H,T,H)

(H,H,H)(T,T,T)

(H,H,H)(H,H,H)(H,H,H)(H,H,H)(T,T,T)(T,T,T)(T,T,T)(T,T,T)

Question 20(CO 2) Consider the table below

Response (number of cats owned) Frequency

None 659

One 329

Two 52

Three 13

Four or more 8

What is the probability that the next person asked has only two cats?

31%

50%

62%

5%

Question 21 Consider the table below

Age Group Frequency

18-29 9831

30-39 7845

40-49 6869

50-59 6323

60-69 5410

70 and over 5279

What is the probability that the next person chosen will be in the 50-59 or 60-69 age groups?

28.2%

23.7%

42.5%

31.7%

Question 22(CO 2) According to company records, the probability that a dishwasher will need repairs during its first six years is 0.09. This is an example of which type of probability?

Subjective probability

Public probability

Empirical probability

Classical probability

Question 23(CO 2) Consider the table below.

Age Group Frequency

18-29 9831

30-39 7845

40-49 6869

50-59 6323

60-69 5410

70 and over 5279

What is P(30-49â€™)?

35.4%

76.3%

64.6%

18.9%

Question 24(CO 2) You are selling your product at a three-day event. Each day, there is a 60% chance that you will make money. What is the probability that you will make money all three days?

0.288

0.144

0.096

0.216

Question 25(CO 2) Consider the table below.

Profit Loss Total

Urban location 50 38 88

Rural location 61 84 125

Total 111 132 243

Find the probability that a randomly selected location is going to be profitable, given that it is in a rural location.

48.8%

55.0%

51.4%

45.7%

Question 26(CO 2) Consider the table below.

Production location Correct Defective Total

East 258 31 289

West 572 106 678

North 755 94 849

South 491 74 565

Total 2076 305 2381

Find the probability that a randomly selected product is from the North, given that it is correct.

88.9%

36.4%

12.1%

87.2 %

Question 27(CO 2) Classify these events. Selecting a king from a deck of cards, keeping it and selecting a queen from the same deck. These events would be considered:

Independent

Subjective

Dependent

Empirical

Question 28 (CO 2) Classify these events. Some customers purchase lots of items and some customers use shopping carts. These events would be considered:

Dependent

Classical

Subjective

Independent

Question 29 (CO 2) In a survey of 320 customers, 58 say that service is poor. You select two customers without replacement to get more information on their satisfaction. What is the probability that both say service is poor?

3.24%

3.19%

3.20%

3.29%

Question 30(CO 2) Randomly select a customer that purchases tofu. Randomly select a customer that purchases chicken. Are these events mutually exclusive?

Non-mutually exclusive events

Mutually exclusive events

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