Question: The average life of a 100-watt lightbulb is stated on the package to be 750 hours. The quality control director at the plant making the lightbulbs needs to check whether the statement is correct. The director is only concerned about a possible reduction in quality and will stop the production process only if statistical evidence exists to conclude that the average life of a lightbulb is under 750 hours. A random sample of 20 bulbs is collected and left on until they burn out. The lifetime of each bulb is recorded. The data are (in hours of continuous use)
738, 752, 710, 701, 689, 779, 650, 541, 902, 700, 488, 555, 870, 609, 745, 712, 881, 599, 659, 793.
Should the process be stopped and corrected? Explain why or why not.