Barstow Community College Statistics Exam Practice

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Express the confidence interval using the indicated format.

Flag question: Question 1

Question 11
.25 pts

Express the confidence interval 0.039 < p < 0.479 in the form of p ± E.

Group of answer choices0.259 – 0.220.259 ± 0.220.259 ± 0.50.22 ± 0.5

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Solve the problem.

Flag question: Question 2

Question 21.25 pts

The following confidence interval is obtained for a population proportion, p: (0.688, 0.724). Use these confidence interval limits to find the point estimate, p^

Group of answer choices0.6880.7060.7240.708

Flag question: SpacerAssume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. Round the margin of error to four decimal places.

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Question 31.25 pts

95% confidence; n = 380, x = 50

Group of answer choices0.03400.03570.03060.0408

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Question 41.25 pts

99% confidence; n = 5900, x = 1770

Group of answer choices0.01350.01540.008780.0117

Flag question: SpacerUse the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

Flag question: Question 5

Question 51.25 pts

n = 56, x = 30; 95% confidence

Group of answer choices0.426 < p < 0.6460.404 < p < 0.6680.425 < p < 0.6470.405 < p < 0.667

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Question 61.25 pts

n = 109, x = 65; 88% confidence

Group of answer choices0.523 < p < 0.6690.518 < p < 0.6740.522 < p < 0.6700.519 < p < 0.673

Flag question: SpacerUse the given data to find the minimum sample size required to estimate the population proportion.

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Question 71.25 pts

Margin of error: 0.005; confidence level: 96%; p and q unknown

Group of answer choices32,02442,01852,14842,025

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Question 81.25 pts

Margin of error: 0.06; confidence level: 96%; p^ and q^
unknown

Group of answer choices326292311225

Flag question: Question 9

Question 91.25 pts

Margin of error: 0.04; confidence level: 95%; from a prior study, p^ is estimated by the decimal equivalent of 60%.

Group of answer choices5771441996519

Flag question: Question 10

Question 101.25 pts

Margin of error: 0.07; confidence level: 95%; from a prior study, p^ is estimated by the decimal equivalent of 92%.

Group of answer choices51174458Flag question: SpacerSolve the problem.

Flag question: Question 11

Question 111.25 pts

A newspaper article about the results of a poll states: “In theory, the results of such a poll, in 99 cases out of 100 should differ by no more than 5 percentage points in either direction from what would have been obtained by interviewing all voters in the United States.” Find the sample size suggested by this statement.

Group of answer choices54427385664

Flag question: SpacerUse the given degree of confidence and sample data to construct a confidence interval for the population mean μ. Assume that the population has a normal distribution.

Flag question: Question 12

Question 121.25 pts

n = 10, x¯ = 8.1, s = 4.8, 95% confidence

Group of answer choices4.67 < μ < 11.534.68 < μ < 11.524.72 < μ < 11.485.32 < μ < 10.88

Flag question: Question 13

Question 131.25 pts

n = 30, x = 84.6, s = 10.5, 90% confidence

Group of answer choices81.36 < μ < 87.8480.68 < μ < 88.5279.32 < μ < 89.8881.34 < μ < 87.86

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Question 141.25 pts

Thirty randomly selected students took the calculus final. If the sample mean was 95 and the standard deviation was 6.6, construct a 99% confidence interval for the mean score of all students.

Group of answer choices92.03 < μ < 97.9791.69 < μ < 98.3191.68 < μ < 98.3292.95 < μ < 97.05

Flag question: Question 15

Question 151.25 pts

A savings and loan association needs information concerning the checking account balances of its local customers. A random sample of 14 accounts was checked and yielded a mean balance of $664.14 and a standard deviation of $297.29. Find a 98% confidence interval for the true mean checking account balance for local customers.

Group of answer choices$492.52 < μ < $835.76$453.59 < μ < $874.69$455.65 < μ < $872.63$493.71 < μ < $834.57

Flag question: SpacerUse the given information to find the minimum sample size required to estimate an unknown population mean μ.

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Question 161.25 pts

Margin of error: $135, confidence level: 95%, a = $500

Group of answer choices46537437

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Question 171.25 pts

How many women must be randomly selected to estimate the mean weight of women in one age group. We want 90% confidence that the sample mean is within 3.4 lb of the population mean, and the population standard deviation is known to be 25 lb.

Group of answer choices147208145148

Flag question: SpacerUse the confidence level and sample data to find a confidence interval for estimating the population μ. Round your answer to the same number of decimal places as the sample mean.

Flag question: Question 18

Question 181.25 pts

Test scores: n = 104, x¯ = 95.3, a = 6.5; 99% confidence

Group of answer choices93.7 < μ < 96.993.8 < μ < 96.894.1 < μ < 96.594.2 < μ < 96.4

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Question 191.25 pts

A random sample of 104 light bulbs had a mean life of x = 543 hours with a standard deviation of a = 26 hours. Construct a 90% confidence interval for the mean life, μ, of all light bulbs of this type.

Group of answer choices536 hr < μ < 550 hr537 hr < μ < 549 hr539 hr < μ < 547 hr538 hr < μ < 548 hr

Flag question: Question 20

Question 201.25 pts

A laboratory tested 82 chicken eggs and found that the mean amount of cholesterol was 228 milligrams with a = 19.0 milligrams. Construct a 95% confidence interval for the true mean cholesterol content, μ, of all such eggs.

Group of answer choices223 mg < μ < 232 mg224 mg < μ < 232 mg225 mg < μ < 233 mg223 mg < μ < 231 mg