Please help me! I am stuck on this chapter and this question seemed to have it all, so its probably the best one to ask. Thank you!

Let X and Y denote the weights in grams of male and female gallinules. Assume that X is and

a) Given n=16 observations of X and m=13 observations of Y, define a test statistic and critical region for testing the null hypothesis against the one-sided alternative hypothesis . Let and assume variances are equal.

b) Given that , calculate the value of the test statistic and make conclusion

c) Test whether the assumption of equal variances is valid. Let .

d) Despite the fact that is accepted in part (c), let us say we suspect the equality is not valid. Thus use the test proposed by Welch.

Thank you for even looking! I am ready to tear my hair out trying to understand this entire chapter. I hope someone out there can help me!