Question

The weights of running shoes are normally distributed with an unknown population mean and standard deviation. If a random sample of 31 running shoes is taken to estimate the mean shoe weight, what t-score should be used to find a 98% confidence interval estimate for the population mean

Answer 1

The t-score is t = 2.457.

Explanation:

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 31 - 1 = 30

98% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 30 degrees of freedom(y-axis) and a one-tailed confidence level of
`1 - (1 - 0.98)/(2) = 0.99`. So we have T = 2.457.

The t-score is t = 2.457.