Question

The lifetime for a certain brand of widgets is normally distributed. A random sample of 25 widgets is taken and a sample mean lifetime of 520 hours with a standard deviation of 50 hours. Before taking the sample, researchers claimed that the mean lifetime of a widget was more than 500 hours. 1. null hypothesis:

2. the alternative hypothesis:
3. explain what test will be used and why?

Answer 1

1. H0: u = 500

2. H1: u <500

3. One sample t test

Explanation:

1. The null hypothesis in this question would be

H0: u = 500

2. The alternative hypothesis would be

H1: u < 500

3. The test that we are going to be using is the one sample t test. This test is used to test hypothesis. It would make a comparison of h0 to the mean of the sample. Now we are using this here because the sample standard deviation was given