Bowker's Test Research Articles

Efficacy and safety of ramipril in long-term treatment of congestive heart failure

The long-term efficacy and safety of ramipril, a long-acting angiotensin-converting enzyme inhibitor, were evaluated in 126 patients with moderate-to-severe congestive heart failure (New York Heart Association [NYHA] functional classes II to IV at baseline) in an open, multicenter trial lasting 96 weeks. An improvement in functional class, peripheral edema, and pulmonary congestion was evident after 2 weeks. At 12 weeks, improvement had reached a plateau, which was maintained throughout the 92 weeks of treatment; 89.3% of patients showed an improvement in NYHA class from baseline to endpoint. The improvements in peripheral edema and pulmonary congestion were statistically significant for change from baseline to endpoint ( P < 0.001, P < 0.0001, respectively; Bowker's symmetry test). Secondary variables of congestive heart failure, such as orthopnea and nocturnal dyspnea, also improved substantially. There were no significant changes in laboratory variables. Ramipril is an effective and well-tolerated therapy for the long-term treatment of patients with moderate-to-severe congestive heart failure.

Change and stability in adult intellectual functioning assessed by Wechsler item responses.

Change in adult intellectual performance was assessed with longitudinal data from the Intergenerational Studies at the Institute of Human Development. Wechsler Intelligence data from two age cohorts spanning ages 18 to 61 were analyzed at the subtest and item level. Hotelling T2 analyses on sets of equivalent items from Wechsler subtests were studied to determine if change in response occurred between pairwise combinations of occasions of test administrations. We used Bowker's test to analyze data at the item level to determine the direction of change in performance. Consistent improvement in performance occurred between the ages of 18-40 and 18-54. Between the ages of 40 and 61, results showed mostly improved performance on the Information, Comprehension, and Vocabulary subtests, mixed change on the Picture Completion subtest, and decline on the Digit Symbol and Block Design subtests. The pattern of mixed change on the Picture Completion subtest indicated improvement on the easy items and decline on the difficult items. Decline in performance on the Block Design test occurred only for the most difficult items.

A note on latent trait theory and Bowker's test

Bowker's test for marginal equality in contingency tables provides a familiar chi-square test to determine whether the marginal distributions are the same across two or more factors or occasions. In this note it is shown how latent trait theory provides a theoretical framework for the development and application of this test.

A Computer Program for the Analysis of Categorical Data

A computer program is described which performs the Bowker test of symmetry in a square contingency table, the Light-Margolin and Pearson tests for homogeneity in non-ordered contingency tables, the Kruskal-Wallis test for ordered dependent variables, and the Kendall and Maxwell tests for monotonic trend in ranks. The description includes the input, output, limitations, and availability of the program.