For subject i, yi = (yi1,…, yid)

T are d repeated measures on a response variable. Consider a model by which yi ∼ N(????,????????) with ????1 = ⋯ = ????d and

???? = corr(yij, yik) for all j ≠ k. The hypothesis of interest is H0: ????1 = ⋯ = ????d.

a. Express this scenario as a marginal model for a multivariate response, and show how to express H0 in terms of the model parameters.

b. Construct a random-effects model for this scenario that would have the specified correlation structure.

c. For d = 2, find a test statistic formula for H0: ????1 = ????2 (e.g., the paireddifference t test of Exercise 9.6).