To investigate methods of reducing fatigue among employees whose jobs involve a monotonous assembly procedure, 12 randomly selected employees were asked to perform their usual job under each of three trial conditions. As a measure of fatigue, the experimenter used the number of assembly line stoppages during a 4-hour period for each trial condition.

a. What type of experimental design has been used in this experiment?
b. Use the appropriate nonparametric test to determine whether the distribution of assembly line stoppages (and consequently worker fatigue) differs for these three conditions. Test at the 5% level of significance.

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Condition:s Employee 1 31 22 20 5 23 26 21 31 22 32 12 16 18 22 29 34 26 18 28 17 26 15 41 31 19 19 25 31 34 41 18 12 46 9 10 12 21