17. Audiology Research In a study to establish the absolute threshold of hearing, 70 male college freshmen were each seated in a soundproof room and a 150 H tone was presented at a large number of stimulus levels in a randomized order. The student was asked to press a button if he detected the tone; the experimenter recorded the lowest stimulus level at which the tone was detected. The mean for the group was 21.6 dB with s52.1. Estimate the mean absolute threshold for all college freshmen and calculate the margin of error