AnswersCA-Statistics and Probability BIntroduction to Confidence Intervals

Introduction to Confidence Intervals Answers

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A city library selects a random sample of 1,250 of its patrons and finds that the 90% confidence interval for the proportion of those who have read an e-book in the previous 12 months is (0.71, 0.75).

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Blank 1:0.73
Blank 2:0.02
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0.02

164088

A nationwide poll asked a random sample of US adults the question, “Are you in favor of making Election Day a federal holiday?” Based on the results of this poll, the 95% confidence interval for the population proportion who favor making Election Day a federal holiday is (0.64, 0.70). Calculate the point estimate and margin of error for the given confidence interval. Enter both values to 2 decimal places. The point estimate = The margin of error =

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Blank 1:0.67
Blank 2:0.03
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0.03

164090

The chamber of commerce for a beach town asked a random sample of city dwellers, “Would you like to live at the beach?” Based on this survey, the 95% confidence interval for the population proportion of city dwellers who would like to live at the beach is (0.56, 0.62). Calculate the point estimate and margin of error for the given confidence interval. Enter both values to 2 decimal places. The point estimate = The margin of error =

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Part 1:0.59
Part 2:0.03
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Question text not available

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0.03

164092

A city library selects a random sample of 1,250 of its patrons and finds that the 90% confidence interval for the proportion of those who have read an e-book in the previous 12 months is (0.71, 0.75). Calculate the point estimate and margin of error for the given confidence interval. Enter both values to 2 decimal places. The point estimate = . The margin of error = .

Answers:
Part 1:0.73
Part 2:0.02
164093

A nationwide poll asked a random sample of US adults the question, "Are you in favor of making Election Day a federal holiday?” Based on the results of this poll, the 95% confidence interval for the population proportion who favor making Election Day a federal holiday is (0.64, 0.70).Interpret the confidence interval.

A
We are 95% confident that less than half of US adults favor making Election Day a federal holiday.
B
95% of the time between 64% and 70% of US adults favor making Election Day a federal holiday
C
We are 95% confident that the interval from 0.64 to 0.70 captures the true proportion of US adults who favor making Election Day a federal holiday.
D
95% of US adults are in favor of making Election Day a federal holiday by a margin of 64 to 70.
164094

The chamber of commerce for a beach town asked a random sample of city-dwellers, "Would you like to live at the beach?” Based on this survey, the 95% confidence interval for the population proportion of city-dwellers who would like to live at the beach is (0.56, 0.62).Interpret the confidence interval.

A
95% of city-dwellers would like to live at the beach approximately half of the time.
B
We are 95% confident that approximately half of all city-dwellers would like to live at the beach.
C
95% of the time between 56% and 62% of city-dwellers would like to live at the beach.
D
We are 95% confident that the interval from 0.56 to 0.62 captures the true proportion of city-dwellers who would like to live at the beach.
164095

A city library selects a random sample of 1,250 of its patrons and finds that the 95% confidence interval for the proportion of those who have read an e-book in the previous 12 months is (0.71, 0.75).Interpret the confidence interval.

A
We are 95% confident that the interval from 0.71 to 0.75 captures the true proportion of library patrons who have read an e-book in the previous 12 months.
B
We are 95% confident that more than half of the library’s patrons have read an e-book in the previous 12 months.
C
95% of the time between 71% and 75% of library patrons have read an e-book in the previous 12 months.
D
The library can be 95% confident that its patrons would be in favor of it offering e-books.
164096

Use the confidence interval to evaluate this claim and select the true statement.

A
Yes, it is reasonable to assume this because we are 95% confident.
B
Yes, it is reasonable to assume this because another 95% confidence interval might contain 0.67.
C
No, it is not reasonable to assume this because there are only two choices and the proportion of adults who should prefer either is exactly equal.
D
No, it is not reasonable to assume this because 0.75 is above the upper boundary of the confidence interval.
164097

Use the confidence interval to evaluate this claim and select the true statement.

A
Yes, it is reasonable to assume this because all reasonable values in the confidence interval are greater than 0.50.
B
We cannot determine this without taking a census of all city-dwellers.
C
No, it is not reasonable to assume this because another 95% confidence interval might not be entirely above 0.50.
D
No, it is not reasonable to assume this because there are only two choices and the proportion of city-dwellers who should prefer either is exactly 0.50, not more than 0.50.
164098

Does the confidence interval give evidence that e-books should be offered?

A
We cannot determine this without surveying all library patrons.
B
No, it is not reasonable to assume enough patrons might use the service because another 95% confidence interval might contain 0.75.
C
No, it is not reasonable to assume enough patrons might use the service because 0.75 is at the very top of the confidence interval.
D
Yes, it is reasonable to assume enough patrons might use the service because 0.75 is included within the confidence interval.

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