Ch 11 Quiz Level 2 COMM 291 BUSI 291 101 Application of Statistics in Business PDF

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11/16/2019

Ch 11 Quiz Level 2: COMM 291 BUSI 291 101 Application of Statistics in Business

Ch 11 Quiz Level 2 Due No due date Points 13.5 Allowed Attempts Unlimited

Questions 14

Time Limit None

Instructions Use Excel to calculate exact values and avoid rounding errors.

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Attempt History Attempt

Time

Score

KEPT

Attempt 2

8 minutes

13.5 out of 13.5

LATEST

Attempt 2

8 minutes

13.5 out of 13.5

Attempt 1

29,474 minutes

11.5 out of 13.5

 Correct answers are hidden. Score for this attempt: 13.5 out of 13.5 Submitted Nov 16 at 7:02am This attempt took 8 minutes.

Question 1

1 / 1 pts

Use the following information for questions 1-3. Hoping to lure more shoppers downtown, a city builds a new public parking garage in the central business district. The city plans to pay for the structure through parking fees. For a random sample of 44 weekdays, daily fees collected averaged $126, with a standard deviation of $15. Suppose that for budget planning purposes, the city needs a better estimate of the mean daily income from parking fees. Complete parts (a) through (c). (a) Someone suggests that the city use its data to create a 95% confidence interval instead of the 90% interval the city first created. Would this increased https://canvas.ubc.ca/courses/40195/quizzes/142961

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Ch 11 Quiz Level 2: COMM 291 BUSI 291 101 Application of Statistics in Business

interval be better for the city? (You do not need to actually create the interval.)

Yes. A 95% confidence level gives increased confidence that the mean parking revenue is contained with the interval.

Question 2

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(b) Would the 95% confidence interval be worse for the planners?

Yes. The increased confidence level creates a wider interval and is, therefore, less precise.

Question 3

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1 / 1 pts

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Ch 11 Quiz Level 2: COMM 291 BUSI 291 101 Application of Statistics in Business

(c) How could they achieve a confidence interval estimate that would better serve their planning needs?

They could collect a larger sample which would create a more precise interval without sacrificing confidence.

Question 4

1 / 1 pts

Use the following information for questions 4-8. A company with a large fleet of cars hopes to keep gasoline costs down and sets a goal of attaining a fleet average of at most 9 litres per 100 kilometres. To see if the goal is being met, they check the gasoline usage for 50 company trips chosen at random, finding a mean of 9.74 L/100 km and a standard deviation of 1.79 L/100 km. Is this strong evidence that they have failed to attain their fuel economy goal? Complete parts a through e below. a) Write appropriate hypotheses. Which hypotheses below will test if the company failed to attain their goal?

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Ch 11 Quiz Level 2: COMM 291 BUSI 291 101 Application of Statistics in Business

H0: μ=9 HA: μ>9

Question 5

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b) Are the necessary assumptions to perform inference satisfied?

Yes, all the necessary assumptions are satisfied or can be assumed to be satisfied.

Question 6

2 / 2 pts

c) Test the hypothesis and find the P-value.

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Ch 11 Quiz Level 2: COMM 291 BUSI 291 101 Application of Statistics in Business

The test statistic is 2.92

. (Round to two decimal places as

needed.) The P-value is 0.003

. (Round to three decimal places as

needed.)

Answer 1: 2.92 Answer 2: 0.003

Question 7

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d) Explain what the P-value means in this context. Choose the correct answer below.

The P-value is the probability of obtaining a sample mean of 9.74 l/100 km or more if the mean mileage of the fleet is 9 l/100 km.

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Ch 11 Quiz Level 2: COMM 291 BUSI 291 101 Application of Statistics in Business

1 / 1 pts

Question 8 e) State an appropriate conclusion. Use α = 0.05. Since the P-value is [ Select ] significance, the data

than the given level of

[ Select ]

sufficient evidence to

reject the null hypothesis.

Answer 1: less

Answer 2: provide

Question 9

1 / 1 pts

Use the following information for questions 9-14. What are the chances your flight will leave on time? Below are a histogram and summary statistics for the percentage of flights departing on time each month from 2001 to 2006. There is no evidence of a trend over time. (The correlation of On Time Departure % with time is r = 0.009 .) Complete parts a through c below.

a) Check the assumptions and conditions for inference. Is the independence assumption met? https://canvas.ubc.ca/courses/40195/quizzes/142961

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Ch 11 Quiz Level 2: COMM 291 BUSI 291 101 Application of Statistics in Business

Yes

Question 10

0.5 / 0.5 pts

Is the randomization condition met or is the sample suitably representative?

Yes

Question 11

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Is the 10% condition met?

Yes

Question 12

0.5 / 0.5 pts

Is the nearly Normal condition met?

Yes

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Ch 11 Quiz Level 2: COMM 291 BUSI 291 101 Application of Statistics in Business

1 / 1 pts

Question 13

b) The 90% confidence interval for the true percentage of flights that depart on time is ( 79.77

flight,

80.87

flights). (Round to

two decimal places as needed, answer in ascending order.)

Answer 1: 79.77 Answer 2: 80.87

Question 14

1 / 1 pts

c) Interpret this interval for a traveller planning to fly. Choose the correct answer below.

We can be 90% confident that the interval contains the true mean monthly percentage of on-time departures.

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Ch 11 Quiz Level 2: COMM 291 BUSI 291 101 Application of Statistics in Business

Quiz Score: 13.5 out of 13.5

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