The effect of guessing on the point estimate of coefficient alpha has been studied in the literature, but the impact of guessing and its interactions with other test characteristics on the interval estimators for coefficient alpha has not been fully investigated. This study examined the impact of guessing and its interactions with other test…

The distance between nonparametric and parametric item characteristic curves has been proposed as an index of goodness of fit in item response theory in the form of a root integrated squared error index. This article proposes to use the posterior distribution of the latent trait as the nonparametric model and compares the performance of an index…

Kelly's formula estimates sampling variance of correlation corrected for attenuation by using split-half reliabilities. In some cases, coefficient alpha estimate of reliability is preferable. A simulation study suggests a variation of Kelly's formula can be used appropriately with coefficient alpha. Kelly's formula is modified to accept…

Empirical evidence is presented related to the effects of using a stratified sampling of items in multiple matrix sampling on the accuracy of estimates of the population mean. Data were obtained from a sample of 600 high school students for a 36-item mathematics test and a 40-item vocabulary test, both subtests of the Iowa Tests of Educational…

Four different procedures were used for estimating the proportion of persons who would be classified consistently as either passing both of two parallel tests or failing both. These four methods were applied at each of four different mastery level scores for each of three different length tests. Data were based on 50 replications of each procedure…