Excel 2003: T-test Add in Data Analysis: Calculating T with Excel:
You may however wish to see the T value calculated rather than simply go direct to the value of P. The following method is for Microsoft Excel 2003.
Method: You may have to put an 'add-in' into your tool menu.
1. Open TOOLS and look to see if you have Data Analysis on the menu.
a. If you have this proceed to step........
b. If you do not have have the Data Analysis package proceed to step 2.
2. Open the TOOLS menu
a. Go 'Add ins"
b. Select Analysis ToolPak.c. OK. You have now added the Data Analysis option to the TOOLS menu. Proceed to Step 3.
3. 
Select : t-Test : Two sample assuming unequal variance
4. 
Specify the ranges of data and the location of the results.
5. Results:
The value of t (t Stat) is -4.53744, which we can round off to -4.54
The probability of this result being due to chance can be read from the table as 0.000291 (two-tail) which means that this result is significant at the .0003 level. We will set our critical P value as .05, so we will say that p < .05.
The null hypothesis is rejected since calculated P = 0.003 < P =0.05 two-tailed test