normal curve


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Related to normal curve: standard deviation

normal curve

a frequency distribution which has a bell-shaped symmetrical pattern where it is possible to calculate the height of the curve (the frequency) corresponding to any given numerical value.

Normal curves are used in statistical QUALITY CONTROL to establish the limits of variation in the size or other characteristic of a product which is to be regarded as acceptable in SAMPLES of a product being tested. For example, if a component is intended to measure an average of 100 mm across and the standard deviation is 2 mm, then the testers would expect 95% of a sample of components to measure between 96 mm and 104 mm across, and 99% of the sample to measure between 94 mm and 106 mm across. If the latter range of sizes was felt be acceptable in terms of the technical performance of the product, then this confidence interval would lead to the whole batch of components being rejected if more than 1% of sample components were larger or smaller than these broad limits. By contrast, if a tougher criterion was imposed and only components measuring 96 mm to 104 mm across were to be regarded as technically acceptable, then 95% of sample components would be acceptable. and if more than 5% of the sample were larger or smaller than these size limits then the whole batch of components would be rejected.

References in periodicals archive ?
We have [h.sup.1](H, I[Z.sub.C[intersection]H,H](3)) = d - 13 if and only if C [intersection] H is contained in a rational normal curve of H.
where [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and 1/[R.sub.g] (i = 1,2) are geodesic curvatures of the parameter curves and the normal curve, respectively.
Majority showed normal curve with left shift and mild broad base curve.
This provides additional information about risk because you can see what extreme values might be possible or, by using normal curve probabilities, determine the probability of a value occurring within an interval or above or below a specific value.
Regularities of this distribution allow determining the frequency of most empirical series, although the curve of the last variation deviates from the normal curve. The bulk of the analyzed cells are characterized by normal diploid chromosomes for cattle--79.80%, yak--78.60%, horses 74,56% and sheep--75.89%.
Students in special education--that is, students with exceptionalities--are operationally defined with reference to their position on the normal curve. Students are identified as having intellectual disabilities, for example, if their tested IQs place them on the lower reaches of the normal curve (i.e., at least 2 SDs below the norm).
As stated above, T scores are adjusted to fit the normal curve, so the distribution of T scores is not skewed.
The Five Integrative Topics: A View from the Past Normal Curves. At the time of my first exposure, psychology was a discipline that focused only on the left--side the "painful" or "deficient" side--of the normal curve.
Every null normal curve lying fully in [E.sup.4.sub.1] is a second kind null osculating curve.
You'd find the normal curve and there right at the top end, spiking on its own, would be the Fiat Panda.
Our result showed that 52 patients had a normal curve of Spee, 33 had a deep curve and 15 had a flat curve of Spee.
For all vehicle types, except motorized 2-wheelers, the histogram assumed a normal curve. Therefore, for these categories, normal distribution was selected to represent the field values.