If an interval estimate is said to be constructed at the 90% confidence level, the confidence coefficient would be a..1 b..95 C..9 d..05 If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the a. width of the confidence interval to increase b.width of the confidence interval to decrease c. width of the confidence interval to remain the same d. sample size to increase In determining the sample size necessary to estimate a population proportion, which of the following is NOT needed? a. the maximum margin of error that can be tolerated b. the confidence level required c. a preliminary estimate of the true population proportion p d. the mean of the population It is known that the population variance equals 484. With a 95 probability, the sample size that needs to be taken to estimate the population mean if the desired margin of error is 5 or less is a. 25 b. 74 C. 189 d. 75 1 = (2012) 0 E2 It is known that the variance of a population equals 1,936. A random sample of 121 has been selected from the population. There is a .95 probability that the sample mean will provide a margin of error of a. 7.84 or less