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 20.25, 24, 16, 13.5, 18, 15.75 and for the other printer, Company B, it took 19, 26.75, 12, 14, 18, 12 seconds. Can they conclude that Company A is more efficient than Company B? Use 5% significance level. b) State a condition that must be true for the above test to be valid