In: Statistics and Probability
Question 9 (1 point)
To design a new advertising campaign, Ford Motor Company would
like to...
Question 9 (1 point)
To design a new advertising campaign, Ford Motor Company would
like to estimate the proportion of drivers of the new Ford Fusion
that are women. In a random sample of 90 Fusion owners, 50 of them
were women. What is the 90% confidence interval estimating the
proportion of all drivers who are women?
Question 9 options:
Question 10 (1 point)
The owner of a local supermarket believes the average number of
gallons of milk the store sells per day is 311.2. In a random
sample of 22 days, the owner finds that the average number of
gallons sold was 281.3 with a standard deviation of 30.12. Using
this information, the owner calculated the confidence interval of
(270.3, 292.3) with a confidence level of 90%. Which of the
following statements is the best conclusion?
Question 10 options:
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1)
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We are 90% confident that the average number of gallons sold
per day is less than 311.2. |
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2)
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The average number of gallons sold per day is not signficantly
different from 311.2. |
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3)
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The percentage of days on which more than 311.2 gallons of milk
are sold is 90%. |
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4)
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We are 90% confident that the average number of gallons sold
per day is greater than 311.2. |
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5)
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We cannot determine the proper interpretation based on the
information given. |
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Question 11 (1 point)
A restaurant wants to test a new in-store marketing scheme in a
small number of stores before rolling it out nationwide. The new ad
promotes a premium drink that they want to increase the sales of.
12 locations are chosen at random and the number of drinks sold are
recorded for 2 months before the new ad campaign and 2 months
after. The average difference in nationwide sales quantity before
the ad campaign to after (after - before) is 0.5 with a standard
deviation of 9.41. Using this information, they calculate a 90%
confidence paired-t interval of (-4.38, 5.38). Which of the
following is the best interpretation?
Question 11 options:
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1)
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We are 90% confident that the difference between the average
sales after the ad campaign and the average sales before the ad
campaign is between -4.38 and 5.38. |
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2)
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We are 90% confident that the average difference in the sales
quantity after to before of the stores sampled is between -4.38 and
5.38. |
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3)
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We are 90% confident that the average difference in sales
quantity between after the ad campaign to before for all
restaurants is between -4.38 and 5.38. |
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4)
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We are certain the average difference in sales quantity between
after the ad campaign to before for all stores is between -4.38 and
5.38. |
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5)
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The proportion of all stores that had a difference in sales
between after the ad campaign to before is 90%. |
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