A study of the relationship between age and various visual functions.pdf

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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 scleral lamina (mm2) from human optic nerve heads: 2.72 2.70 2.70 3.91 2.27 2.76 3.91 4.22 3.97 4.31 3.44 4.51 2.48 3.56 2.88 3.53 2.98 (a) Calculate ?xi and ?xi^2. (Round ?xi^2 to two decimal places.) (b) Use the values calculated in part (a) to compute the sample variance s^2 and then the sample standard deviation s. (Round your answers to three decimal places.) Solution s = 0.687.

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