The average annual health care cost in a random sample of 600 U.S.adults is $8562.If the standard deviation for health care costs in the population is $1230, compute the margin of error in a 90% confidence interval estimate of the mean annual health care cost for all U.S.adults.
A)82.8
B)86.2
C)91.3
D)87.7
E)90.3

Question

Quizplus · Accepted Answer

The margin of error is:ME = z * (sigma / sqrt(n))where z is the z-score for the desired confidence level, sigma is the population standard deviation, and n is the sample size.For a 90% confidence level, z = 1.645.Plugging in the values, we get:ME = 1.645 * (1230 / sqrt(600)) = 82.8Therefore, the margin of error is $82.8.

The Average Annual Health Care Cost in a Random Sample