A Social Researcher Claims That the Average Adult Listens to the Radio

Essay

A social researcher claims that the average adult listens to the radio less than 26 hours per week.He collects data on 25 individuals' radio listening habits and finds that the mean number of hours that the 25 people spent listening to the radio was 22.4 hours.If the population standard deviation is known to be eight hours,can we conclude at the 1% significance level that he is right?