We learned in Example 9.7.1 that the purpose of a study by Kwast-Rabben et al. (A-6) was to analyze somatosensory evoked potentials (SEPs) and their interrelations following stimulation of digits I, III, and V in the hand. Healthy volunteers were recruited for the study. Researchers applied stimulation below-pain-level intensity to the fingers. Recordings of spinal responses were made with electrodes fixed by adhesive electrode cream to the subject’s skin. Results are shown in the following table for 114 subjects. Use multiple regression to see how well you can predict the peak spinal latency (Cv) of the SEP for digit I when age (years) and arm length (cm) are the predictor variables. Evaluate the usefulness of your prediction equation.

Age Arm Length Cv Dig.I Age Arm Length Cv Dig.I Age Arm Length Cv Dig.I 35.07 76.5 13.50 32.00 82.0 16.30 42.08 94.0 17.70 35.07 76.5 13.50 32.00 82.0 15.40 40.09 94.0 17.70 21.01 77.0 13.00 38.09 86.5 16.60 40.09 94.0 17.40 21.01 77.0 13.60 38.09 86.5 16.00 42.09 92.5 18.40 47.06 75.5 14.30 58.07 85.0 17.00 20.08 95.0 19.00 47.06 75.5 14.90 58.07 85.0 16.40 50.08 94.5 19.10 26.00 80.0 15.40 54.02 88.0 17.60 50.08 94.5 19.20 26.00 80.0 14.70 48.10 92.0 16.80 47.11 97.5 17.80 53.04 82.0 15.70 48.10 92.0 17.00 47.11 97.5 19.30 53.04 82.0 15.80 54.02 88.0 17.60 26.05 96.0 17.50 43.07 79.0 15.20 45.03 91.5 17.30 26.05 96.0 18.00 39.08 83.5 16.50 45.03 91.5 16.80 43.02 98.0 18.00 39.08 83.5 17.00 35.11 94.0 17.00 43.02 98.0 18.80 43.07 79.0 14.70 26.04 88.0 15.60 32.06 98.5 18.30 29.06 81.0 16.00 51.07 87.0 16.80 32.06 98.5 18.60 29.06 81.0 15.80 51.07 87.0 17.40 33.09 97.0 18.80 50.02 86.0 15.10 26.04 88.0 16.50 33.09 97.0 19.20 25.07 81.5 14.60 35.11 94.0 16.60 35.02 100.0 18.50 25.07 81.5 15.60 52.00 88.5 18.00 35.02 100.0 18.50 25.10 82.5 14.60 44.02 90.0 17.40 26.05 96.0 19.00 47.04 86.0 17.00 44.02 90.0 17.30 26.05 96.0 18.50 47.04 86.0 16.30 24.05 91.0 16.40 25.08 100.5 19.80 37.00 83.0 16.00 24.00 87.0 16.10 25.06 100.0 18.80 37.00 83.0 16.00 24.00 87.0 16.10 25.06 100.0 18.40 34.10 84.0 16.30 24.00 87.0 16.00 25.08 100.5 19.00 47.01 87.5 17.40 24.00 87.0 16.00 30.05 101.0 18.00 47.01 87.5 17.00 53.05 90.0 17.50 30.05 101.0 18.20 30.04 81.0 14.10 53.05 90.0 17.50 36.07 104.5 18.90 23.06 81.5 14.20 52.06 90.0 18.00 36.07 104.5 19.20 23.06 81.5 14.70 52.06 90.0 17.90 35.09 102.0 21.00 30.04 81.0 13.90 53.04 93.0 18.40 35.09 102.0 19.20 78.00 81.0 17.20 22.04 90.0 16.40 21.01 101.5 18.60 41.02 83.5 16.70 22.04 90.0 15.80 21.01 101.5 18.60 41.02 83.5 16.50 46.07 95.5 18.80 40.00 95.5 20.00 28.07 78.0 14.80 46.07 95.5 18.60 42.09 92.5 18.40 28.07 78.0 15.00 47.00 93.5 18.00 42.08 94.0 18.50 36.05 88.0 17.30 47.00 93.5 17.90 35.04 86.0 16.00 35.04 86.0 15.30 39.05 94.5 17.40 36.05 88.0 16.60