You conduct a survey of 100 randomly chosen Berkeley students, asking each one how often they get their hair cut. You conduct a two-tailed test using the standard value of with the null hypothesis that the mean time between haircuts in the population is 4 weeks. In which circumstance can you reject the null hypothesis?

a 95% confidence interval for the mean does not include 4 weeks.

Explanation:

The null hypothesis which states that the mean time between haircuts in the population is 4 weeks should be rejected if at 95% confidence interval,the means does not include 4 weeks. That is, that at 95% confidence interval, the probability of a student getting a haircut in 4 weeks is lower than 0.05. It means that the probability of a student getting a haircut in 4 weeks is lower than 5 in 100 cases.

no because it could make the world a terrible place to live in.