Barstow Community College Statistics Questions

ExamName___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Express the confidence interval using the indicated format.
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1) Express the confidence interval 0.039 < p < 0.479 in the form of p ± E. A) 0.259 ± 0.22 B) 0.259 - 0.22 C) 0.22 ± 0.5 D) 0.259 ± 0.5 Solve the problem. 2) 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. A) 0.706 B) 0.724 C) 0.708 1) 2) D) 0.688 Assume 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. 3) 95% confidence; n = 380, x = 50 3) A) 0.0340 B) 0.0408 C) 0.0357 D) 0.0306 4) 99% confidence; n = 5900, x = 1770 A) 0.0154 B) 0.00878 C) 0.0117 D) 0.0135 4) Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p. 5) n = 56, x = 30; 95% confidence 5) A) 0.404 < p < 0.668 B) 0.405 < p < 0.667 C) 0.425 < p < 0.647 D) 0.426 < p < 0.646 6) n = 109, x = 65; 88% confidence A) 0.518 < p < 0.674 C) 0.523 < p < 0.669 6) B) 0.519 < p < 0.673 D) 0.522 < p < 0.670 Use the given data to find the minimum sample size required to estimate the population proportion. ^ ^ 7) Margin of error: 0.005; confidence level: 96%; p and q unknown A) 42,018 B) 42,148 C) 32,024 ^ D) 42,025 ^ 8) Margin of error: 0.06; confidence level: 96%; p and q unknown A) 225 B) 292 C) 311 D) 326 ^ 9) Margin of error: 0.04; confidence level: 95%; from a prior study, p is estimated by the decimal equivalent of 60%. A) 577 B) 1441 C) 996 D) 519 ^ 10) Margin of error: 0.07; confidence level: 95%; from a prior study, p is estimated by the decimal equivalent of 92%. A) 4 B) 58 C) 174 D) 51 1 7) 8) 9) 10) Solve the problem. 11) 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. A) 27 B) 544 C) 664 D) 385 11) Use 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. 12) n = 10, x = 8.1, s = 4.8, 95% confidence A) 4.68 < µ < 11.52 B) 4.67 < µ < 11.53 C) 5.32 < µ < 10.88 13) n = 30, x = 84.6, s = 10.5, 90% confidence A) 81.34 < µ < 87.86 C) 79.32 < µ < 89.88 B) 80.68 < µ < 88.52 D) 81.36 < µ < 87.84 D) 4.72 < µ < 11.48 12) 13) 14) 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. A) 91.69 < µ < 98.31 B) 91.68 < µ < 98.32 C) 92.95 < µ < 97.05 D) 92.03 < µ < 97.97 14) 15) 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. A) $493.71 < µ < $834.57 B) $492.52 < µ < $835.76 C) $453.59 < µ < $874.69 D) $455.65 < µ < $872.63 15) Use the given information to find the minimum sample size required to estimate an unknown population mean µ. 16) Margin of error: $135, confidence level: 95%, = $500 16) A) 53 B) 74 C) 37 D) 46 17) 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. A) 145 B) 148 C) 147 D) 208 17) Use 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. 18) Test scores: n = 104, x = 95.3, = 6.5; 99% confidence A) 94.2 < µ < 96.4 B) 94.1 < µ < 96.5 C) 93.8 < µ < 96.8 D) 93.7 < µ < 96.9 19) A random sample of 104 light bulbs had a mean life of x = 543 hours with a standard deviation of = 26 hours. Construct a 90% confidence interval for the mean life, µ, of all light bulbs of this type. A) 538 hr < µ < 548 hr B) 536 hr < µ < 550 hr C) 539 hr < µ < 547 hr D) 537 hr < µ < 549 hr 2 18) 19) 20) A laboratory tested 82 chicken eggs and found that the mean amount of cholesterol was 228 milligrams with = 19.0 milligrams. Construct a 95% confidence interval for the true mean cholesterol content, µ, of all such eggs. A) 224 mg < µ < 232 mg B) 223 mg < µ < 232 mg C) 225 mg < µ < 233 mg D) 223 mg < µ < 231 mg 3 20)