The Number of Degrees of Freedom for a Paired T $\left( X _ { 1 } , Y _ { 2 } \right) , \left( X _ { 2 } , Y _ { 2 } \right) , \ldots \ldots , \left( X _ { n } , Y _ { m } \right)$

Short Answer

The number of degrees of freedom for a paired t test, where the data consists of n independently pairs $\left( X _ { 1 } , Y _ { 2 } \right) , \left( X _ { 2 } , Y _ { 2 } \right) , \ldots \ldots , \left( X _ { n } , Y _ { m } \right)$ is __________.