7. In a test of the ability of a certain polymer to remove toxic wastes from water, experiments were conducted at three different temperatures. The data below give the percentages of the impurities that were removed by the polymer in 21 independent attempts.

Test the hypothesis that the polymer performs equally well at all three temperatures.
Use the

(a) 5 percent level of significance and

(b) 1 percent level of significance.

Transcribed Image Text:

Low Temperature Medium Temperature High Temperature 42 41 36 33 35 44 37 32 40 29 38 36 35 39 44 40 42 37 32 34 45