A psychologist is collecting data on the time it takes to learn a certain task.For 50 randomly selected adult subjects,the sample mean is 16.40 minutes and the sample standard deviation is 4.00 minutes.Construct the 95% confidence interval for the mean time required by all adults to learn the task.
A)[8.56 24.24]
B)[15.47 17.33]
C)[16.24 16.56]
D)[15.29 17.51]
E)[17.12 48.48]

Question

Quizplus · Accepted Answer

The formula for the confidence interval is:mean +/- z * (standard deviation / square root of sample size)where z is the z-score corresponding to the desired confidence level. For a 95% confidence level, z = 1.96.Plugging in the values we have:16.40 +/- 1.96 * (4.00 / sqrt(50))= 16.40 +/- 1.96 * (4.00 / 7.07)= 16.40 +/- 1.96 * 0.566= 16.40 +/- 1.11So the 95% confidence interval is (15.29, 17.51).

A Psychologist Is Collecting Data on the Time It Takes