# Thread: Finding a P-value

1. ## Finding a P-value

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

2. Originally Posted by bluehorseshoe33
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).

3. ## Hmmmm...

The homework software gave me .1171 for the first one. Totally lost now.

4. Originally Posted by bluehorseshoe33
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).

 Tweet

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts