Exam 8: Confidence Interval Estimation

(A) You can be 95% confident that the mean salary for all production managers with at least 15 years of experience is between what two numbers (the t-multiple with 8 degrees of freedom is 2.306). What assumption are you making about the distribution of salaries? ​ (B) What sample size would be needed to ensure that we could estimate the true mean salary of all production managers with more than 15 years of experience and have only 5 chances in 100 of being off by more than $4200?

A parameter such as is sometimes referred to as a(n) ____ parameter, because many times, we need its value even though it is not the parameter of primary interest.

If we cannot make the strong assumption that the variances of two samples are equal, then we must use the pooled standard deviation in calculating the standard error of a difference between the means.

Confidence intervals are a function of the: