a. What type of parametric test would you use, and why, in the following scenario? The skills of male and female twin pairs in mathematics are assessed, and the average math performances (i.e., scores on a standardized test) of the gender groups are compared. What type of nonparametric test could you use and why (i.e., under what conditions)? What tests (parametric and nonparametric) would you use if the males and females were not related to one another (i.e., separate samples)?
b. What sampling decisions need to be made (i.e., how many students do you need, and should you use probability or nonprobability sampling methods and why?) to study the best method of teaching first-grade students how to spell? Describe how sampling error can be affected by the sampling method you select.