A public policy research group is conducting a study of health care plans and would like to estimate the average dollars contributed annually to health savings accounts by participating employees. A pilot study conducted a few months earlier indicated that the standard deviation of annual contributions to such plans was $1,225. The research group wants the study's findings to be within $100 of the true mean with a confidence level of 90%. What sample size is required?
A) 407
B) 361
C) 512
D) 546

Question

Quizplus · Accepted Answer

The sample size required can be calculated using the formula:n = (Z^2 * s^2) / e^2where:n is the sample sizeZ is the z-score for the desired confidence levels is the standard deviatione is the margin of errorPlugging in the given values, we get:n = (1.645^2 * 1225^2) / 100^2n = 406.96Rounding up to the nearest whole number, the required sample size is 407.

A Public Policy Research Group Is Conducting a Study of Health