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ERIC Number: ED365706
Record Type: Non-Journal
Publication Date: 1993-Apr
Pages: 22
Abstractor: N/A
Reference Count: N/A
Type I Error Rates for Welch's Test and James's Second-Order Test under Nonnormality and Inequality of Variance when There Are Two Groups.
Algina, James; And Others
Type I error rates were estimated for three tests that compare means by using data from two independent samples: the independent samples t test, Welch's approximate degrees of freedom test, and James's second order test. Type I error rates were estimated for skewed distributions, equal and unequal variances, equal and unequal sample sizes, and a range of total sample sizes. Welch's test and James's test have very similar Type I error rates and tend to control the Type I error rate as well or better than the independent samples t test does. The results provide guidance about the total sample sizes required for controlling Type I error rates. Nine tables are included. (Contains 16 references.) (Author)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A