Four laboratories are being employed to carry out chemical analysis. Samples of same material are sent to the laboratories for analysis as part of the study to determine whether or not they give, on average, the same results. Suppose the distributions of results for the laboratories are of same shape but not normal. The analytical results of the sample material are as follows:
A B C D
58.7 62.7 55.9 60.7
61.4 64.5 56.1 60.3
60.9 63.1 57.3 61.4
59.1 59.2 55.2 60.9
58.2 60.3 58.1 62.3
Test if the laboratories give the same results on average. Use a = 0.005.