SOME STATISTICAL CONCEPTS IN THE ANALYSIS OF VISION AND VISUAL ACUITY
作者:
J. M. Wild,
M. K. Hussey,
期刊:
Ophthalmic and Physiological Optics
(WILEY Available online 1985)
卷期:
Volume 5,
issue 1
页码: 63-71
ISSN:0275-5408
年代: 1985
DOI:10.1111/j.1475-1313.1985.tb00637.x
出版商: Blackwell Publishing Ltd
数据来源: WILEY
摘要:
Abstract—As conventionally recorded, visual acuity data constitute an ordinal scale of measurement. An investigation of four different clinical samples shows that visual acuity is not normally distributed amongst these populations. Furthermore, acuity is often measured on charts which, by the inherent restriction of the stimulus size, have the effect of truncating the upper limit of the scale producing, in statistical terms, an incomplete distribution. The distribution of acuity for each sample is found to be adequately described in terms of the equation:F(x) =Axα(T‐x)β, whereF(x) is the cumulative distribution of the statistical population,Tis the truncation level (known),xis the Snellen decimal acuity (known) andA, α and β are parameters. Alternative analytical procedures based upon this model, which overcome these limitations, are di
点击下载:
PDF
(479KB)
返 回