The Student T-test

The Student T-test

1. The Student’s t-test is a statistical test that compares the mean and standard deviation of two samples to see if there is a significant difference between them.

   • The T-test is a test of a statistical significant difference between two groups.

2. How to calculate T:

   • Calculate the mean (X) of each sample
     • Calculate the standard deviation for each sample
       • Square the standard deviation for each sample
         • Divide each squared standard deviations by the sample size of that group.
           • Add these two values
             • Take the square root of the number to find the "standard error of the difference.
               • Divide the difference in the means by the standard error of the difference.
                 • Determine the degrees of freedom (df) for the test. In the t-test, the degrees of freedom is the sum of the sample sizes of both groups minus 2
                   • Determine the “Critical T-value” in a table by triangulating your DF and the “p value” of 0.05.

3. Where:

   • •x1 is the mean of sample 1
   • •s1 is the standard deviation of sample 1
   • •n1 is the sample size of sample 1
   • •x2 is the mean of sample 2
   • •s2 is the standard deviation of sample 2
   • •n2 is the sample size in sample 2

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