Please explain how you get the answer step by step and make it clear to understa
ID: 3067280 • Letter: P
Question
Please explain how you get the answer step by step and make it clear to understand. Thanks! It is widely believed that a person's level of fitness prior to undergoing corrective knee surgery is an important factor in the speed of rehabilitation following surgery. A study was undertaken with 24 randomly selected male subjects who were to undergo such surgery. The physical fitness status of each subject before the surgery was categorized as being below average (n 8), average (n-10), or above average (n # 6). Following surgery, the number of days spent in physical therapy by each patient until fully Examination of side-by-side boxplots indicated that it was reasonable to assume that the samples came from populations with equal standard deviations. The following ANOVA table was obtained. (Some entries have been replaced with. Analysis of Variance Source Status DF Sum of Squares Mean Square FRatio P.ralue 672.0 336.0 Error Total 1088.0 2 ? What is the value of the estimate for the common population variance, ? A) 4.45 B) 336.0 C) 47.3 D) 20.40 E) None of the above a iExplanation / Answer
The Common population Variance is the mean square error or MSE.
There are 3 columns, below average, average and above average, and therefore the df of between = n -1 = 3 - 1 = 2
The total observations = 8 + 10 + 6 = 24. The degrees of freedom for the denominator = N - c = 24 - 3 = 21
The Sum of squares of error, SSE = SStotal - SS status = 1088 - 672 = 416
The MSE = SSE/df error = 416/21 = 19.80
Therefore (E), none of the above.