Originally Posted by

**MHoffman**
Hello All,

I'm doing a paired t-test with a data set close to 1300. We're looking at pain scales from before and after treatment. When I run the test (with excel and graphpad.com) I'm getting a P-Value of 0...so I keep thinking something is wrong. I've posed the output information below from excel.

Am I doing the right test? And is it possible to have P-value of 0 (I would have expected something along the lines of 0.0008E-14 or something, but just 0 makes me a little concerned that something is wrong with either the way I set up the test in excel or with how my data is arranged).

Any help would be appreciated.

Thank you!

t-Test: Paired Two Sample for Means

Variable 1 - In Level --- Variable 2 - Out Level

Mean 6.141263238 --- 3.436649017

Variance 4.246730954 --- 3.455152805

Observations 1322 --- 1322

Pearson Correlation 0.510524044

Hypothesized Mean Difference 0

df 1321

t Stat 50.5080754

P(T<=t) one-tail 0

t Critical one-tail 1.646007938

P(T<=t) two-tail 0

t Critical two-tail 1.961761371