If Y is distributed \(\chi \)2, then Pr(Y ≤ 21.60) is ? The answer is .75 but not sure how to get there.

18

(edit: Should say \(\chi \)2 over 18 but not sure how to type that)

HoldMyBeer May 1, 2022

#1**+3 **

I think you mean that 18 is the number of degrees of freedom! Look in some chi-square distribution tables (e.g. https://en.wikibooks.org/wiki/Engineering_Tables/Chi-Squared_Distibution) along the row for DF = 18 until you get to a number close to 21.6, then look at the column heading for the probability.

(NB: In the reference above the probabilities represent greater than rather than less than, so you would need to subtract the resulting probability from 1 for your case.)

Alan May 2, 2022