For each of the following sets of data, (1) calculate the mean of the scores (left(mathrm{X}^{-} ight),(2))

For each of the following sets of data, (1) calculate the mean of the scores \(\left(\mathrm{X}^{-}\right),(2)\) calculate the deviation of each score from the mean \(\mathrm{X}-\mathrm{X}^{-}\), and (3) check to see if the sum of the deviations equals zero \(\sum \mathrm{X}-\mathrm{X}^{-}=0\).

a. \(7,5,12\)

b. \(6,7,9,12\)

c. \(6,8,4,11,3,7\)

d. \(5,7,3,1,4,8,5,2,7,9,12,4,15\)