(5) #106. Previously, an organization reported that teenagers spent 4.5 hours per week, on average, on the phone. The organization thinks that, currently, the mean is higher. Fifteen randomly chosen teenagers were asked how many hours per week they spend on the phone. The sample mean was 4.75 hours with a sample standard deviation of 2.0. At a significance level of a = 0.05, what is the correct conclusion? a. There is enough evidence to conclude that the mean number of hours is more than 4.75 b. There is enough evidence to conclude that the mean number of hours is more than 4.5 c. There is not enough evidence to conclude that the mean number of hours is more than 4.5 d. There is not enough evidence to conclude that the mean number of hours is more than 4.75