Sample size
Refer to the formula14 n = (μα + μβ) 2σd2 / δd2, where μα and μβ can be found in the μ value table, σd is the standard deviation of the difference, and δd is the difference. After looking up the table, μα = 1.960, μβ = 1.280, and σd = 0.038 and δd = 0.028 were pre-tested by the research group, and 45 samples of each group were calculated. Considering the 10% test exit rate, the overall calculation was finally obtained.We
Use random number table method to group.