A researcher constructs a five-item measure of attitudes toward national health insurance. The average intercorrelations among the items is r_ii = .40. Using the Spearman-Brown formula, he finds that R^SB = .77. What is the reliability of the scale as a whole? A) .77 B) .50 C) .40 D) Cannot be determined without knowing the sample size.

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Quizplus · Accepted Answer

The reliability of the scale as a whole is given by the result of the Spearman-Brown formula, which in this case is .77. This formula is used to estimate the reliability of a scale based on the average inter-item correlation and the number of items in the scale.

A Researcher Constructs a Five-Item Measure of Attitudes Toward National