Suppose that you want to compare the means of several treatments in a randomized block ANOVA. If given the choice between using the randomized block ANOVA test and the Friedman test, which one would you choose if outliers occur in the sample data? Explain your answer.

In a randomized block ANOVA, identify the statistic that is used as a measure of variationa. among the sample means for the treatments.b. among the sample means for the blocks.c. within the samples for the treatments with the variation due to blocks removed.

A researcher compares differences in positivity between participants in a low-, middle-, or upper-middle-class family. If she observes 15 participants in each group, then what are the degrees of freedom for the one-way between-subjects ANOVA?

Acne is a common skin disease that affects most adolescents and can continue into adulthood. A study compared the effectiveness of three acne treatments and a placebo, all in gel form, applied twice daily for 12 weeks. The study's 517 teenage volunteers were randomly assigned to one of the four treatments. Success was assessed as clear or almost clear skin at the end of the 12 week period. The results of the study can be seen in the table below. Using the appropriate statistical test, determine if there is significant evidence that the four treatments perform differently. If so, how do they compare.

Car and Driver Magazine tested a random sample of 9 hybrid cars and found their MPG to be 42, 51, 39, 44, 52, 48, 51, 44, and 47. Construct a 95% confidence interval for the population variance.

Suppose in a two-way ANOVA table,the total sample size N is 30, factor Ahas 3 levels, and the degrees of freedom for interaction is 8. What is the degrees of freedom for error?