The use of electrical stimulation (ES) to increase muscular strength is discussed in the Journal of Orthopedic and Sports Physical Therapy. Seventeen healthy volunteers participated in the experiment. Muscular strength, Y, was measured as a torquein foot-pounds, and ES, X, was measured in mA (microamps). The equation for the line of best fit is given as Y = 1.8x + 28.7, and the Pearson correlation coefficient was 0.61.
a. Was the correlation coefficient significantly different from zero? Use α = 0.05.
b. Predict the torque for a current equal to 50 mA.