The following data comes from a capability study whose characteristic of

quality is measured in mm. The results correspond to six samples of 4

pieces each.

... Sample board

We want to check if the data associated with the quality characteristic are distributed

according to a normal law. The calculation of the variance of this data series must be

calculated.

... Board for calcul differences

a) Complete the missing values in the table above (to three decimal places).

b) Determine the experimental value of W.

c) Specify the decision rule to be adopted, at the 10% significance level.

d) Can we conclude, at the 10% significance level, that the characteristic of

quality is not distributed normally? Explain.