8.21 Suppose that it is known that the quotient of the population made up of children between 9 and 13 years old has a mean of 45. An inverted person wants to test the hypothesis that the mean of a subgroup of that population is greater, for which he takes a sample of size 30 of that subgroup and find the statistics X = 49.05 and Sx = 14.80. He tests the inverter hypothesis with a = 0.05. What is the observed level of significance of the sample? What would be the conclusion with a = 0.10 ? Assume Normal distribution.