An auto battery company claims that their batteries mean life is 50 months. In order to check this claim, a DTI researcher took a random sample of 18 of these batteries and found that the mean life is 48.8 months with standard deviation of 7 months. Assume that the battery life follows a normal distribution, test with 90% confidence whether the companies claim is different from the true mean.

An auto battery company claims that their batteries mean life is 50 months. In order to check this claim, a DTI researcher took a random sample of 18 of these batteries and found that the mean life is...

An auto battery company claims that their batteries mean life is 50 months. In order to check this claim, a DTI researcher took a random sample of 18 of these batteries and found that the mean life is 48.8 months with standard deviation of 7 months. Assume that the battery life follows a normal distribution, test with 90% confidence whether the companies claim is different from the true mean.

Jun 08, 2022