The simple answer to this question is that correlation is the standardized form of covariance. Both Correlation and Covariance describe the degree of similarity between two variables. Correlation: When you say that two items correlate, you are saying that the change in one item effects a change in another item. You will always talk about […]
arnold on Sep 17, 2008
Reliability is the desired consistency (or reproducibility) of test scores. In practical terms reliability is the degree to which individual’ deviation scores, or z-scores, remain relatively consistent over repeated administration of the same test or alternate test forms (Crocker and Algina, 1986, p. 105). Test developers must demonstrate that the scores obtained are reliable otherwise […]
arnold on Sep 17, 2008
1) The mean of the error scores for a population of examinees is zero. 2) The correlation between true and error scores for a population of examinees is zero. 3) When examinees take two seperate tests and each examinee’s score on the two tests (or two testing occasions with the same form) are assumed to […]
arnold on Sep 17, 2008
This could be answered best by the Horan et al (2003) article. Their Research Question: Do wording-effects represent a distinctive response style rather than a purely artificial result? How do we interpret the two-factor exploratory structure produced by the use of both positively and negatively worded items? Should these factors be interpreted as two separate […]
arnold on Sep 16, 2008
Bartlett et al (1960) asked this same question. This brief article briefly compared the Likert-Type measurement against the forced choice option. The authors argue that the traditional type (Likert-Type) of attitude measurement may be subject to many types of bias, for instance the desire to raise expectation on a post-test to provide positive reinforcement that […]
arnold on Sep 16, 2008
Schriesheim and Castro (1996) did the study on this. THE BASIC ARGUMENT:Prior literature mainly used ‘sometimes’ as the referent. So what would happen if the referent that the frequency expressions were tied to was changed? Would it enhance confidence placed on the magnitude estimation technique (MET) through proof of invariance or undermine the confidence placed […]
arnold on Sep 16, 2008