几个问题求助？

A study was made on the effects of several health additives for a number of elite runners. The results of a one-way ANOVA are presented in the following table. What are the MS values?
Source Df Sum of Squares MS
Between 3 55.00
Within 15 450.50
Total 18 505.50

A. 55.0, 450.50, 505.50
B. 55.0, 450.50
C. 18.3, 30.0, 28.1
D. 18.3, 30.0

Why is the normality assumption essential to the interpretation of the capability index?
A. Because a spread of 6 standard deviations represents 99.73% of cases
B. Because only normal distributions are capable of statistical control
C. Because the specifications are always explained by the bell curve
D. Because the normal distribution always has a mean of 0

When performing “one experiment with five repetitions,” what are the six experiments called?
A. Randomization
B. Replications
C. Planned grouping
D. Sequential

The diameter of a population of ball bearings is normally distributed with a mean of 75 and a standard deviation of 8. What is the probability of the average diameter of 10 randomly selected ball bearings being greater than 77?
A. 0.3751
B. 0.4013
C. 0.2146
D. 0.0210