The average number of cavities that thirty year old Americans have had in their lifetimes is 5 Do twenty year olds have fewer cavities The data show the results of a survey of 13 twenty year olds who were asked how many cavities they have had Assume that the distribution of the population is normal Use the classical approach 3 6 4 6 4 4 4 6 5 6 5 6 5 What can be concluded at the a 0 05 level of significance a For this study we should use t test for a population mean b The null and alternative hypotheses would be Ho P H P