Repeated Measurements Analysis of Variance when the Correlations have a Certain Pattern

Consider a repeated measurements study in which a single observation is taken at each of t(t > 2) equally spaced time points for each of n subjects. This paper uses a result of Box to find the appropriate multiplicative correction term for the degrees of freedom in the analysis of variance table for the case when there is equal variability per time point, and when the correlation between observations u time units apart is equal to ρu. For large values of t, the multiplicative correction has a lower bound approximately equal to 2.5/(t − 1).