. The mean yield of corn in the United States is about 135 bushels per acre. A survey of 50 farmers this year gives a sample mean yield of x = 138.4 bushels per acre. We want to know whether this is good evidence that the national mean this year is not 135 bushels per acre. Assume that the farmers surveyed are an SRS from the population of all commercial corn growers and that the standard deviation of the yield in this population is Ïƒ = 10 bushels per acre. Report the value of the test statistic z, give a sketch illustrating the P-value and report the P-value for the test of
H0: Î¼ = 135
Ha: Î¼ _= 135
Are you convinced that the population mean is not 135 bushels per acre? Is your conclusion correct if the distribution of corn
yields is somewhat non-Normal? Why?