Calculate the mean of the population sample. This will be the sum of scores in the population sample divided by the number of members in the sample. This may be represented mathematically as ? = ? xi/n, where \"?\" is the sample mean, \"xi\" is the score for the \"ith\" member of the sample and \"n\" is the number of members in the sample.
Derive the mean of the entire population. This is similar to the sample mean and is given as X = ? xi/n, where \"X\" is the population mean, \"xi\" is the score for the \"ith\" member of the population and \"n\" is the number of members in the population.
Determine the sample’s standard deviation. T test values are measured in units of standard deviation which you can calculate as s = ( ? ( xi - ? )2 / ( n - 1 ) ) ^(1/2). \"S\" is the sample’s standard deviation, \"xi\" is the score for the \"ith\" member of the sample, \"?\" is the mean of the population sample and \"n\" is the number of members in the sample.
Calculate the T test value as T = ( x - X ) / ( s / n^2). \"T\" is the T test value, \"x\" is the sample mean, \"X\" is the population mean, \"s\" is the sample's standard deviation and \"n\" is the number of members in the sample.