Question

The speeds of vehicles traveling on a highway are normally distributed with an unknown population mean and standard deviation. If a random sample of 38 vehicles is taken to estimate the mean vehicle speed, what t-score should be used to find a 99% confidence interval estimate for the population mean

Answer 1

The t-score of 2.715 should be used

Explanation:

Degrees of freedom ==> n - 1 ==> 38 - 1 ==> 37

to find 99% confidence interval, Hence,

Find t0.005 in front of 37 degrees of freedom,

Therefore the answer is, t-score = 2.715