chi-square distribution with $v = 7$ degrees of freedom Ti-89? I need to figure out the Probability that $Y > 23$ for a chi-square distribution with degrees of freedom $= 7$. The book says to do this with some applet. I don't know what it's talking about. Can I do this on my Ti-89 (preferable) or on some website somewhere? **EDIT/UPDATE:** I found a program on my ti-89 for chi-square distribution. However it asks me for lower and upper bound and degrees of freedom. I put in $7$ for degrees of freedom but i'm not sure how to translate probability $Y > 23$ into an upper and lower bound? I put in lower $= 0$, upper $= 23$, degrees of freedom $= 7$ and I said to auto-scale and I got $.998295$. Is that the right probability?

There's an online calculator here. Plugging $\chi^2 = 23$ and $df=7$, we get $.0017$. Your calculator calculated the probability that $0 \leq \chi^2 \leq 23$, which is $1-.0017 = .9983$.

As I commented above, you could tell that you needed to take $1-p$ instead of $p$ since $\chi^2 > 23$ is an unlikely event, given that the expectation is $7$ and the standard deviation is $\sqrt{14} \approx 4$ (Chebyshev and even Markov would give you that $p < 1/2$).