A True Score would be the average of observed scores obtained over an infinite number of repeated testings with the same test. The essence of Spearman model was in that any observed test score could be envisioned as the composite of two hypothetical components- a true score and a random error component: X=T+E, where X- […]
arnold on Oct 05, 2008
Semantic differential is a type of a rating scale designed to measure the connotative meaning of objects, events, and concepts. The respondent is asked to choose where his or her position lies, on a scale between two bipolar words, or a range of words or numbers ranging across a bipolar position (for example, `Excellent’, `Good’, […]
arnold on Oct 05, 2008
Statistical properties of the item score are examined through a variety of procedures known as item analysis. Item Analysis furnishes a variety of statistical data regarding how subjects responded to each item and how each item relates to overall performance. If an item analysis is conducted on a preliminary form of a test, the next […]
arnold on Oct 05, 2008
Interval scales are often referred as “equal interval scales.” Consequently a) the rank ordering of objects on an attribute is known, b) the distances among objects on the attribute are also known, but c) the absolute magnitudes of the attribute are unknown. Deviation from any mean can be calculated without actually knowing how far anyone […]
arnold on Oct 05, 2008
With Domain Sampling, tests are constructed by randomly selecting a specified number of measures from a homogeneous, infinitely large pool. A sample of items is reliable to the extent that the score it produces correlates highly with these true scores (Nunnally and Bernstein, 1994, p. 217). This is easier to understand if you look at […]
arnold on Oct 05, 2008
Lets Start With Some Definitions: Cronbach’s Alpha is mathematically equivalent to the average of all possible split-half estimates, although that’s not how we compute it (socialresearchmethods.net). Cronbach’s alpha will generally increase when the correlations between the items increase. For this reason the coefficient is also called the internal consistency or the internal consistency reliability of […]
arnold on Oct 05, 2008