Calculating Partial Eta Squared from Wilk's Lambda


I am doing homework for my multivariate stats class. Our teacher is asking us to calculate the partial eta squared using wilks lambda. The formula is:

[FONT=&quot]ηp = 1 – Λ 1/s[/FONT]

[FONT=&quot]s = the smaller of the degrees of freedom in the formula

I have all the numbers I need for the formula, but I am having trouble doing the problem on my calculator. :(

The problem I have is [FONT=&quot]ηp = 1 – .72 1/3[/FONT]. Would it be possible for someone to tell me how to imput this formula in my calculator? I have a texas instruments calculator (TI-30XIIS) and I just can't figure out how to calculate .72[FONT=&quot]1/3[/FONT] on it. I know the answer to the formula, I just need to figure out how to get it. I haven't been able to find any information online, so hopefully some kind soul will be patient and willing to explain it :)