Finding a P-value

#1
The questions:

Use technology to find the P-value for a right-tailed test with n=26 and test statistic t=1.219

Use technology to find the P-value for a two-tailed test with n=26 and test statistic t= -2.989


I haven't a clue how to do these with my calculator. Can someone point me in the right direction?

Thanks
 

Dragan

Super Moderator
#2
The questions:

Use technology to find the P-value for a right-tailed test with n=26 and test statistic t=1.219

Use technology to find the P-value for a two-tailed test with n=26 and test statistic t= -2.989


I haven't a clue how to do these with my calculator. Can someone point me in the right direction?

Thanks
I'd suggest you use a software package such as Minitab - it's very good for such questions.

For example, t=1.219 (above) the associated p-value is: p=0.116894.

This took me all of about ten seconds:)

If not, then I would recommend that you attempt to make such computations using Microsoft Excel.


Note: when referring to the Student t-distribution we should refer to the associated degrees of freedom (df) rather than n.

For example, t(df=26).
 

Dragan

Super Moderator
#4
The homework software gave me .1171 for the first one. Totally lost now.
Let me explain.

You obtained p=0.1171 because your calculation was based on 25 degrees of freedom (df) as follows:

df = N - 1 = 26 -1 = 25.

As I said above, in the previous post, you need to specify what the degrees of freedom are - it's not always going to be N - 1 (it could be N - 2, for example).