Grade-(x) Dix-

Grade x Mid Point Fre uenc Interval i o s x < 20 10 10 1 20 s x < 40 30 20 2 40 s x < 60 50 40 3 60 s x < 80 70 20 4 80 s -x 100 90 10 5 Try to estimate the mean and the variance by using the mid-point (mi) in each interval. [Hint] The mean and variance should be estimated by the following formulas. s Ei(mt Ft) n (Eifrnt2 Ft)) nx2 Based on these 100 observations, is a Normal distribution an appropriate probability model? Perform a goodness-of-fit test by using the p-value to make your conclusion with a = 0.05. Please clearly type down the hypotheses, test statistic, and p-value for your test. [Hint] Don't try' to use Anderson-Darling Test here. Also, you should pay attention to the boundary of the first and the last intervals. Please remember Normal is a continuous RV and its range is [00, w].