The effects of misspecifying intercept-covariate interactions in a 4 time-point latent growth model were the focus of this investigation. The investigation was motivated by school growth studies in which students' entry-level skills may affect their rate of growth. We studied the latent interaction of intercept and a covariate in predicting growth…

This is a quantitative empirical research study validating the invariance of item difficulty parameters estimates based on the two competing measurement frameworks, the classical test theory (CTT) and the item response theory (IRT). In order to achieve the set goal, one fifty five (155) different independent samples were drawn from the population…

Neater representations for variance are given for small sample sizes, especially for 3 and 4. With these representations, variance can be calculated without a calculator if sample sizes are small and observations are integers, and an upper bound for the standard deviation is immediate. Accessible proofs of lower and upper bounds are presented for…