Suppose a random sample of 36 is selected from a population with a standard deviation of 12.If the sample mean is 98, the 90% confidence interval for the population mean is ___.
A)94.71 to 101.29
B)97.45 to 98.55
C)94.08 to 101.92
D)97.35 to 98.65
E)95.00 to 105.00

Question

Quizplus · Accepted Answer

The 90% confidence interval is calculated using the formula: sample mean ± (Z * (population standard deviation / sqrt(sample size))). For a 90% confidence level, Z is approximately 1.645. Thus, the interval is 98 ± (1.645 * (12 / sqrt(36))) = 98 ± 3.29, which is 94.71 to 101.29.

Suppose a Random Sample of 36 Is Selected from a Population