A random sample of size n is taken from a normal population with variance (9), how large must the sample size (n ) be so that the length of 98% confidence interval for the population mean is 3 O 25 O22 O 30 Next page D-TERM EXAM Jump to... Z-TABLE - e here to search ASUS ZenBook f5 fo f8

A researcher is trying to estimate the population mean for a certain set of data. The sample mean is 20, and the error bound for the mean is 7, at a 68% confidence level. (So, x¯=20 and EBM = 7.) Find and interpret the confidence interval estimate.

Suppose scores on exams in Statistics are normally distributed with an unknown population mean and a sample standard deviation of 3 points. A random sample of scores with sample size equal to 36 gives a sample mean of 68. Find a confidence interval (CI) estimate for the population mean exam score for a) 90% CI and b) 95% CI, separately.

Construct a confidence interval for p₁ - P2₂ at the given level of confidence. x₁ = 30, n₁ = 228, x₂ = 39, n₂ = 294, 95% confidence The researchers are % confident the difference between the two population proportions, p₁ – P2, is between (Use ascending order. Type an integer or decimal rounded to three decimal places as needed.) and

Construct a confidence interval for p, - p, at the given level of confidence. X1 = 398, n1 = 543, x2 = 408, n2 = 578, 99% confidence The researchers are % confident the difference between the two population proportions, p, - p2, is between and (Use ascending order. Type an integer or decimal rounded to three decimal places as needed.)

A sample of 64 is taken from a population, with the mean of the sample being 119 and the standard deviation of the sample being 16. What is the 99.7% confidence interval for the mean of the population? OA. (115, 123) OB. (113, 125) OC. (118, 120) D. (117, 121)

Construct a confidence interval for P₁-P₂ at the given level of confidence. X₁ = 369, n₁ = 508, X₂ = 426, n₂ = 599, 95% confidence % The researchers are confident the difference between the two population proportions, P₁-P₂, is between and (Use ascending order. Type an integer or decimal rounded to three decimal places as needed.)