For each of the following situations, calculate the \(t\)-statistic \((t)\) :

a. \(\mathrm{X}^{-}=20.00 ; \mu=18 ; s \mathrm{X}^{-}=1.00\)

b. \(X^{-}=20.00 ; \mu=13 ; s X^{-}=1.00\)

c. \(X^{-}=12.00 ; \mu=20 ; s X^{-}=1.00\)

d. Looking at your answers to (a-c), how is the \(t\)-statistic affected by the size of the difference between the sample mean and the population mean \(\mathrm{X}^{-}-\mu\) ?