Robert S Atlas
Biographic Data
| ID | 7116520 |
|---|---|
| NAME | Robert S Atlas |
| GIVEN NAMES | Robert S |
| FAMILY NAME | Atlas |
| SIGNATURE | ATLAS R S |
| AFFILIATIONS | The University of Texas-Houston Medical School Houston, Texas |
| VERIFIED | No |
| TOTAL WORKS | 3 |
| TOTAL CITATIONS | 0 |
| AUTHOR COUNT | 3 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1992 |
| LATEST PUBLICATION YEAR | 1995 |
| H-INDEX | 0 |
Tests That are Robust against Variance Heterogeneity in k × 2 Designs with Unequal Cell Frequencies
Heterogeneity of variance produces serious bias in conventional analysis of variance tests of significance when cell frequencies are unequal. Welch in 1938 and 1947 proposed an adjusted t test for the difference between two means when cell frequencies and population variances are both unequal. This article describes two ways to use the Welch t to evaluate the significance of the main effect for two treatments across k levels of a concomitant fact…
Power of a Test That is Robust against Variance Heterogeneity
Welch (1947) proposed an adjusted t test that can be used to correct the serious bias in Type I error protection that is otherwise present when both sample sizes and variances are unequal. The implications of the Welch adjustment for power of tests for the difference between two treatments across k levels of a concomitant factor are evaluated in this article for k x 2 designs with unequal sample sizes and unequal variances. Analyses confirm that,…
Comparison of a Two-Stage and Three-Stage Interim-Analysis Procedure
A statistical model for combining p values from multiple tests of significance is used to define rejection and acceptance regions for two-stage and three-stage sampling plans. Type I error rates, power, frequencies of early termination decisions, and expected sample sizes are compared. Both the two-stage and three-stage procedures provide appropriate protection against Type I errors. The two-stage sampling plan with its single interim analysis en…
No prominent works on this page.
Comparison of a Two-Stage and Three-Stage Interim-Analysis Procedure
A statistical model for combining p values from multiple tests of significance is used to define rejection and acceptance regions for two-stage and three-stage sampling plans. Type I error rates, power, frequencies of early termination decisions, and expected sample sizes are compared. Both the two-stage and three-stage procedures provide appropriate protection against Type I errors. The two-stage sampling plan with its single interim analysis en…
Tests That are Robust against Variance Heterogeneity in k × 2 Designs with Unequal Cell Frequencies
Heterogeneity of variance produces serious bias in conventional analysis of variance tests of significance when cell frequencies are unequal. Welch in 1938 and 1947 proposed an adjusted t test for the difference between two means when cell frequencies and population variances are both unequal. This article describes two ways to use the Welch t to evaluate the significance of the main effect for two treatments across k levels of a concomitant fact…
Power of a Test That is Robust against Variance Heterogeneity
Welch (1947) proposed an adjusted t test that can be used to correct the serious bias in Type I error protection that is otherwise present when both sample sizes and variances are unequal. The implications of the Welch adjustment for power of tests for the difference between two treatments across k levels of a concomitant factor are evaluated in this article for k x 2 designs with unequal sample sizes and unequal variances. Analyses confirm that,…
Mathematics (3 works) · Statistics (3 works) · Analysis of variance (2 works) · Econometrics (2 works) · Economics (2 works) · Optimal Experimental Design Methods (2 works) · Power (physics (2 works) · Psychology (2 works) · Statistical Methods in Clinical Trials (2 works) · Test (biology (2 works)