Inspection of the data for Exercise 11 in Chapter 5 suggests that the data may not be normally distributed. Redo the problem using the MannWhitney test. Compare the results with those obtained by the...

Inspection of the data for Exercise 11 in Chapter 5 suggests that the data may not be normally distributed. Redo the problem using the MannWhitney test. Compare the results with those obtained by the pooled t test

Exercise 11

Chlorinated hydrocarbons (mg/kg) found in samples of two species of fish in a lake are as follows:

Perform a hypothesis test to determine whether there is a difference in the mean level of hydrocarbons between the two species, assuming the population variances are equal. Is the equal variance assumption reasonable?