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The distribution of student's t-statistic for small samples from lognormal exposure distributions.

Authors
Evans-JS; Hawkins-NC
Source
Am Ind Hyg Assoc J 1988 Oct; 49(10):512-515
NIOSHTIC No.
00182974
Abstract
Student's t-statistics were studied as methods of evaluating average exposure when based on small samples from lognormal distributions. In industrial hygiene, the compliance officer's test (for noncompliance) and the factory industrial hygienist's hypothesis test (for compliance) were based on the Student's t-statistic. Actual samplings of small samples were compared with theoretical values. When the geometric standard deviation (GSD) was 1.01 the theoretical and emperical results were nearly the same. When the GSD was greater than 1.01 there was a divergence between the actual and the empirical. The greater the variability the greater the divergence that was observed. The degree of Type-I error was shown to be greater for plant industrial hygienists than predicted but less than predicted for compliance officers. The power of the t- statistic was also studied in conjunction with some recently proposed alternatives. The author concludes that the ordinary t- statistic has some shortcomings especially if the sample is skewed but that some of the problems could be eliminated by the use of t- statistic modifications.
Keywords
NIOSH-Publication; NIOSH-Grant; Statistical-quality-control; Long-term-exposure; Biostatistics; Risk-analysis; Industrial-hygiene
Contact
Physiology Department, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115
CODEN
AIHAAP
Publication Date
19881001
Document Type
Journal Article
Funding Amount
8171719
Funding Type
Grant
Fiscal Year
1989
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-T15-OH-007096; Grant-Number-T42-OH-007096
Issue of Publication
10
ISSN
0002-8894
Priority Area
Training
Source Name
American Industrial Hygiene Association Journal
State
MA
Performing Organization
Harvard University, Boston, Massachusetts
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