A doctor would like to estimate the mean difference in height of pairs of identical twins. The doctor randomly selects 8 pairs of identical twins and determines the current height, in inches, of each twin. The data are displayed in the table. A 3-column table with 8 rows. Column 1 is labeled Pair with entries 1, 2, 3, 4, 5, 6, 7, 8. Column 2 is labeled Twin 1 with entries 66, 64.5, 72, 70, 65, 64.5, 48, 54. Column 3 is labeled Twin 2 with entries 67, 65, 72, 69.5, 63, 49, 54.5. What is the mean difference (twin 1 - twin 2) and the standard deviation of the differences? x Overbar difference = negative 0.125, s difference = 0.834 x Overbar difference = negative 0.696, s difference = 0.834 x Overbar difference = 0.125, s difference = 0.834 x Overbar difference = 0.125, s difference = 0.696