The weights of 300 adult men were estimated and employed to test the hypothesis that the weights were normally distributed with a mean of 160 lb and standard deviation of 15 lb. The data were grouped in the following classes:
Weight (x) Observed Frequency
x < 130 7
130 ≤ x < 145 38
145 ≤ x < 160 100
160 ≤ x < 175 102
175 ≤ x < 190 40
190 ≤ x 13
From the normal table, the percentages for classes are 2.28%, 13.59%, 34.13%, 34.13%, 13.59%, and 2.28%, respectively. Do observed frequency data provide significant reason to discredit the hypothesis that the weights are normally distributed with a mean of 160 lb and a standard deviation of 15 lb? Use α= 0.05.