Browsing by Author "Feldt, Leonard S."

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    A comparison of five methods for estimating the standard error of measurement at specific score levels
    (1985) Feldt, Leonard S.; Steffen, Manfred; Gupta, Naim C.
    The Standards for Educational and Psychological Testing (1985) recommended that test publishers provide multiple estimates of the standard error of measurement-one estimate for each of a number of widely spaced score levels. The presumption is that the standard error varies across score levels, and that the interpretation of test scores should take into account the estimate applicable to the specific level of the examinee. This study compared five methods of estimating conditional standard errors. All five of the methods yielded a maximum value close to the middle of the score scale, with a sharp decline occurring near the extremes of the scale. These trends probably characterize the raw score standard error of most standardized achievement and ability tests. Other types of tests, constructed using alternative principles, might well exhibit different trends, however. Two methods of estimation were recommended: an approach based on polynomial smoothing of point estimates suggested by Thorndike (1951) for specific score levels and a modification proposed by Keats (1957) for the error variance derived under the binomial error model of Lord (1955).
  • Thumbnail Image
    Item
    Statistical inference for coefficient alpha
    (1987) Feldt, Leonard S.; Woodruff, David J.; Salih, Fathi A.
    Rigorous comparison of the reliability coefficients of several tests or measurement procedures requires a sampling theory for the coefficients. This paper summarizes the important aspects of the sampling theory for Cronbach’s (1951) coefficient alpha, a widely used internal consistency coefficient. This theory enables researchers to test a specific numerical hypothesis about the population alpha and to obtain confidence intervals for the population coefficient. It also permits researchers to test the hypothesis of equality among several coefficients, either under the condition of independent samples or when the same sample has been used for all measurements. The procedures are illustrated numerically, and the assumptions and derivations underlying the theory are discussed.
  • Thumbnail Image
    Item
    Test of the hypothesis that the intraclass reliability coefficient is the same for two measurement procedures
    (1992) Alsawalmeh, Yousef M.; Feldt, Leonard S.
    An approximate statistical test is derived for the hypothesis that the intraclass reliability coefficients associated with two measurement procedures are equal. Control of Type 1 error is investigated by comparing empirical sampling distributions of the test statistic with its derived theoretical distribution. A numerical illustration of the procedure is also presented. Index terms: intraclass reliability, reliability, sampling theory, Spearman-Brown extrapolation, statistical test.
  • Thumbnail Image
    Item
    Testing the Equality of Two Related Intraclass Reliability Coefficients
    (1994) Alsawaimeh, Yousef M.; Feldt, Leonard S.
    An approximate statistical test of the equality of two intraclass reliability coefficients based on the same sample of people is derived. Such a test is needed when a researcher wishes to compare the reliability of two measurement procedures and both procedures can be applied to the performances or products of the same group of individuals. A numerical example is presented. Monte carlo studies indicate that the proposed test effectively controls Type I error with as few as two or three measurements on each of 50 people. Index terms: equality of related intraclass reliability coefficients, intraclass reliability, sampling theory, Speannan-Brown extrapolation, statistical test.