A spectrophotometer used for measuring CO concentra- tion [ppm (parts per million) by volume] is checked for accuracy by taking readings on a manufactured gas (called span gas) in which the CO concentration is very precisely controlled at 70 ppm. If the readings suggest that the spectrophotometer is not working properly, it will hav: to be recalibrated. Assume that if it is properly cali- brated, measured concentration for span gas samples is normallyr distributed. 0n the basis of the six readings85, 7?, 82, 68, 72, and 69is recalibration necessary? Carry out a test of the relevant hypotheses using a = .05