= value of T
In the above stated formula the numerator is very simple to evaluate that is only to calculate the difference of mean between two groups but the denominator that is the standard errors of the difference. It is complicated to evaluate which first requires the evaluation of variance then divided it by the total number of people involved in a group which are further added and their square root is taken. Variance is actually the square of the standard deviation. The value of T is determined in a way that if the first mean value is positive then the value of T is supposed to be positive.
References
• Richard Mickiewicz, The Story of Mathematics (Princeton University Press), p.158.
• Zimmerman, Donald W. (1997). "A Note on Interpretation of the Paired-Samples t Test". Journal of Educational and Behavioral Statistics 22 (3): 349–360.
• Moore, David S. (1995), The Basic Practice of Statistics, New York: W. H. Freeman.