Four laboratories are being used to perform chemical analysis. Samples of the same material are sent to the laboratories for analysis as part of the study to determine whether or not they give, on the average, the same results. The analytical results for the four laboratories are as follows:(a) Use Bartlett's test to show that the within-laboratory variances are not significantly different at the Q = 0.05 level of significance.(b) Perform the analysis of variance and give conclusions concerning the laboratories.(c) Does a normal probability plot ofresiduals?

Laboratory D 58.7 62.7 61.4 64.5 60.9 63.1 59.1 59.2 60.3 55.9 60.7 56.1 60.3 57.3 60.9 55.2 61.4 62.3 58.2 58.1