A study of the relationship between age and various visual functions (such as acuity and depth perception) reported the following observations on the area of sclera lamina (mm2) from human optic nerve heads ("Morphometry of Nerve Fiber Bundle Pores in the Optic Nerve Head of the Human," Experimental Eye Research, 1988: 559-568):

a. Calculate ˆ‘xi and oxi2.
b. Use the values calculated in part (a) to compute the sample variance s2 and then the sample standard deviation s.

2.75 2.62 2.74 3.85 2.34 2.74 3.93 4.21 3.88 4.33 3.46 4.52 2.43 3.65 2.78 3.56 3.01