Question

The systolic blood pressure (SBP) of a certain population is normally distributed with standard deviation 6 mmHg. A sample of 24 members of this population was found to have an average SBP of 122 mmHg. Find a 90% confidence interval for the population mean. Round the endpoints to the nearest integer.

Confidence interval is:

The average starting salaries for 48 graduates with a certain major was $42061. The standard deviation for all graduates with that major was $8318. Give the 90% confidence interval for the population mean. Round the endpoints to the nearest dollar, and do not put commas in your numbers.

Confidence interval:

The diameter of the twelve-penny common nails made by ’Snails!, Inc., is normally distributed with standard deviation 0.004 in. A sample of 34 such nails was found to have a mean diameter of 0.127 in. Find a 92% confidence interval for the mean diameter of all such nails. Round the endpoints to five decimal places.

Confidence interval is

f 300 confidence intervals, each having a level of confidence of 91%, were computed for a population mean μ, approximately how many of the intervals would be expected to contain μ?  (Round your answer to the nearest integer.)

What quantity is added to and subtracted from a sample mean to construct a confidence interval?

A. The population mean
B. The standard error
C. The population standard deviation
D. The sample standard deviation
E. The margin of error

Answer 1