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Home Statistical Tests Comparing Variances One Sample ChiSquareTest  
See also: two sample FTest, ChiSquare Distribution, survey on statistical tests  
One Sample ChiSquareTest
Certain problems require not only that the mean conforms to some restrictions, but also that the variance is within certain limits, i.e. not larger than a given value. So we have to compare the estimated sample variance with the hypothetical variance σ^{2}. When the samples are normally distributed, the ratio s^{2}(n1)/σ^{2} follows a χ^{2}distribution (pronounced: chisquare). The upper tails of the distribution have been tabulated (or you may
use the distribution calculator). χ^{2}(α)
depicts the area of α% in the upper tail of
the χ^{2} distribution,
i.e. Prob( χ^{2}
> χ^{2}(α))
= α. The shape of the χ^{2}distribution
depends on the degrees of freedom n1.


Home Statistical Tests Comparing Variances One Sample ChiSquareTest 
Last Update: 20121008