49. A study of the relationship between age and various visual functions (such as acuity and depth perception) reported the following observations on area of scleral 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):

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

a. Calculate
xi and
x 2 i .

b. Use the values calculated in part

(a) to compute the sample variance s2 and then the sample standard deviation s.