How To: Find a p-value with Excel

How to Find a p-value with Excel

This how-to-video helps to find the P-Value using MS excel function tdist. For demonstration this tutorial takes the following examples. Case I: Right tailed Test with n=7 and test statistic t = 3.500 [=tdist(3.5,6,1)]Case II: Left tailed test with n=27 and test statistic t = -1.500 [=tdist(1.5,26,1)]Case III: Two tailed test with n = 21 and test statistic t = 9.883 [=tdist(9.883,20,2)]Case IV: Two tailed test with n= 11 and test statistic t = 2.00 [=tdist(2.00, 10,2)]Copy the above examples to an excel sheet. Case I.Apply the function "=tdist" followed by open parenthesis, add the value of x which stands for value of t in our case it is 3.5. Enter the degrees of freedom which stand for the value of n. For case I value of n is n-1, so it will be 7-1 = 6, finally add the value for tails. The tails value can be either 1 for one tailed test or 2 for two tailed test. Case I is a one tailed test. So the value of tails is 1. Finally your formula should appear like this =tdist (3.5, 6, 1). Press enter. This gives a value of 0.006413 which is the P-value for this test. Case II:Enter the Function =tdist followed by open parenthesis, add the value of x which stands for value of t in our case it is -1.5. Always add positive values. Add x = 1.5, degrees of freedom = 26 (27-1, n-1), and this is a one tailed test. Add 1 as tails value. Press enter. This gives a value of 0.07283 which is the P-value for this test. Case III:Enter the Function =tdist followed by open parenthesis, add the value of x which stands for value of t in our case it is 9.883. Add x= 9.883, degrees of freedom = 20 (21-1, n-1), and this is a two tailed test. Add 2 as tails value. Press enter. This gives a value of 3.85E-09 which is the P-value for this test. Case IV:=tdist Arguments: x =2.00, Degrees of freedom = 10 (11-1, n-1), Tails = 2 ; P - value - 0.073388