A study of the relationship between age and various visual functions (such as acuity and depth perception) reported the followin
g observations on the area of scleral lamina (mm2) from human optic nerve heads: 2.79 2.53 2.78 3.79 2.33 2.72 3.88 4.15 3.79 4.43 3.47 4.47 2.50 3.61 2.77 3.53 3.07 (a) Calculate Σxi and Σxi2. (Round Σxi2 to two decimal places.) Σxi = mm2 Σxi2 = mm4