Question 7
A light bulb used to have an averaged life time of 1000 hours. Now the
factory developed a novel technique hoping to extend its life time. We
randomly pick up 10 light bulbs produced by the new technique and the
measured life time mean value is 1077 hours with the standard deviation of
51.97 hours. If we do the t-test at the significance level of 2.5%, did the new
technology work?
(6 marks)