2. Large-Sample Test of o? = 07: When n 2 30, we can test the null hypothesis that 02 =00, or o = 00, by computing S - 50 2 = Co/ V2n which is a value of a random variable whose sampling distribution is approximately the standard normal distribution under the null hypothesis. A sample surveys conducted in a large county in a certain year shows that the average height of 40 ten-year-old boys was 54 inches with a standard deviation of 2.6 inches. Test at the o = 0.05 level of significance whether o = 2.5 inches against the alternative that o * 2.5 inches using the critical region method