Recall the study, reported in Exercise 7.8.1, in which Dora et al. (A-37) investigated spinal canal dimensions in 30 subjects symptomatic with disc herniation selected for a discectomy and 45 asymptomatic individuals (control group). One of the areas of interest was determining if there is a difference between the two groups in the spinal canal cross-sectional area (cm2

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between vertebrae L5/S1. The data in the following table are simulated to be consistent with the results reported in the paper. Do these simulated data provide evidence for us to conclude that a difference in the spinal canal cross-sectional area exists between a population of subjects with disc herniations and a population of those who do not have disc herniations? Let a ¼ :05.

Herniated Disc Group Control Group 2.62 2.57 1.98 3.21 3.59 3.72 4.30 2.87 3.87 2.73 5.28 1.60 1.80 3.91 2.56 1.53 1.33 2.36 3.67 1.64 3.54 3.63 2.39 2.67 3.53 2.26 2.82 4.26 3.08 3.32 4.00 2.76 3.58 2.05 1.19 3.01 2.39 3.61 3.11 3.94 4.39 3.73 2.22 2.73 2.09 3.79 2.45 2.55 2.10 5.02 3.62 3.02 3.15 3.57 2.37 2.28 2.33 2.81 3.70 2.61 5.42 3.35 2.62 3.72 4.37 5.28 4.97 2.58 2.25 3.12 3.43 3.95 2.98 4.11 3.08 2.22 Source: Simulated data.