a) York University students use printing companies to print their documents in which they complain about the companies being too slow. A student group conducted a study to help determine which type of printing company to choose. In the study, six documents are printed by two different printer companies. The number of seconds it took for Company A to print a document was 18.5, 29, 9, 13.5, 19.5, 15.75 and for the other printer, printer Company B, it took 23. 26.?5, 12, 19, 21. 26 seconds. Can they conclude that Company A is more efcient than Company B? Use 10% signicance level. b) State a condition that must be true for the above test to be valid: c) Solve Part c) independently. Pzer has just developed a medicine for COVID to alleviate the symptoms of COVID. Still. they are concerned about the variability in the amount of time until the medicine becomes effective. In a random sample of 8 individuals who suffer from COVID, the amount of time (in hours) for the medicine to take effect was recorded. \"'3\" represents missing data and some relevant statistics are given below. Estimate with 95% confidence the variability in the amount of time for the medicine to become effective. Amount oftime (X): 12,16, 9, '3', 8, 4, ?, 10 2X = 70, Z 2 = 722, S! = 3.9551