This is very easy to do using Excel (of course). The result of this test is a number between 0 and 1 that represents the probability that the differences between two sets of data are due to random error - this is the p value. Thus a t test that gives the number 0.6 means that there is a 60% chance that the differences in the two sets of data are due to random errors. A value of .01 means there is a 1% chance. Statisticians have decreed that any value from a t test that is < 0.05 (less than 5%) indicates that the two samples sets are statistically different and that the difference is not due to random errors. This is important to remember.
In some cell (you will need to somehow label it - it is not really important which cell you use, as long as it does not interfere with you data input), select the INSERT menu item. Select FUNCTION from the choices. This will bring up a dialog box with two windows. Select STATISTICAL in the top box. The lower box will now be filled with various statistical functions. Scroll the left window and select T-TEST as shown below.
This will start another dialog box with four data windows. Click your cursor in the first one (names ARRAY1. Now select the data in column 1 (if you have 20 data points, you should have 20 cells selected). Do the same with array 2 but select the data in column B. Be sure NOT to select either the average or standard deviation cells.
In the TAILS window, place the number 2 and in the TYPE window, place he number 3 . (see below). Now press OK.
The number that now appears in the cell with the function is the % probability that these two sets of data are NOT different from each other statistically. As stated above, scientists will generally consider different if the % chance that they are not different is less than 5%. So if you do a T TEST and the % comes out at 15%, these data sets are not considered to be different. If they come out to be 2.5%, then they are (and it is reported as < 0.05). Format this cell so that it is colored and so that there are just 2 decimal places. Place some sort of label to identify the data.
In this example, the t test value is 0.09. Since this value is greater than 0.05, we would conclude that these two sets of values are not significantly different. Remember that your values may be different.
Do the same and compare column A with C and compare B with C. You will then need to indicate which sets of data are significantly different. This can be typed into any free cell. Thus you are making three different comparisons (A-B, B-C, and A-C). You should then indicate whether the data are or are not significantly different.
Save the file and email it to me.