Normal Deviate

Abstract We consider statistical criteria for partitioning a reference database to obtain separate reference ranges for different subpopulations. Using general formulas relating population variances, sample sizes, and the normal deviate test for the significance of the difference between two subgroup means, we show that partitioning into separate ranges produces little reduction in between-person variability, even when the differences between means are highly significant statistically. However, when there is a clear physiological basis for distinguishing between certain subgroups, simulation studies show that partitioning may be necessary to obtain reference limits that cut off the desired proportions of low and high values in each subgroup. Guidelines based on these results are provided to help decide whether separate ranges should be obtained for a given analyte.

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Pre-Therapy Adaptation of Stuttering and Its Relation to Speech Measures of Therapy Progress

Journal of Speech and Hearing Research ◽

10.1044/jshr.1104.740 ◽

1968 ◽

Vol 11 (4) ◽

pp. 740-746 ◽

Cited By ~ 6

Author(s):

David Prins

Keyword(s):

Negative Correlation ◽

Oral Reading ◽

Partial Correlation ◽

Correlation Coefficients ◽

Speaking Rate ◽

Normal Deviate ◽

Adaptation Measures ◽

Negative Direction ◽

Therapy Program ◽

Post Therapy

Three measures of stuttering adaptation were obtained on 20 stutterers prior to the beginning of an eight-week residential therapy program. Following therapy each subject was evaluated using six scores which represented changes in speaking rate and frequency of stuttering during oral reading and in self-formulated speech. The results showed that less than half of the stutterers demonstrated a significant adaptation trend (A t ), and only 12 of 20 showed significant normal deviate scores (A s ) of adaptation. Partial correlation coefficients were significant in a negative direction between pretherapy percentage (A p ) and trend (A t ) adaptation measures and post-therapy scores showing increment in reading and speaking rate. It appears that adaptation is neither consistendy nor highly related to speech measures of therapy progress. A rationale is suggested for the negative correlation of adaptation and therapy change scores.

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