Excel CHIINV

The Microsoft Excel functions CHIINV(.025, 4) and CHIINV(.975, 4) give the same values. 

For a two-sided test, the null hypothesis, Hq, is that the variance of the population from which the data giving is drawn is equal to and the alternative hypothesis is that it is not equal. Hq is rejected at the 95% level if r> xEi.025.1,-1 or T < x o.975.11-1 In Excel the probability of a particular value of chi-square is given by =CHIDIST, df), and the critical value of chi-square is =CHIINV( q, df) for probability ct and df degrees of freedom. 

The chi-square distribution is used to perform statistical tests on the sample variance. It is highly asymmetric for small values of n, but becomes more symmetric and similar to a normal distribution as n becomes large, such as 20 or 30. The cumulative distribution function of the chi-square distribution is listed in Table 3.4 as a function of v and a, where v = - 1 is the number of degrees of freedom and a is the percentage of the distribution above the particular Microsoft Excel has built-in functions, CHIDIST and CHIINV, that compute a chi-square distribution [5, 6]. 

Excel 2007 or older norminv finv, chiinv , tinv ... 

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