Mathematics (AS & A Level) · Oct / Nov 2016 · Paper 73 · Question 4

The manufacturer of a tablet computer claims that the mean battery life is 11 hours. A consumer organisation wished to test whether the mean is actually greater than 11 hours. They invited a random sample of members to report the battery life of their tablets. They then calculated the sample mean. Unfortunately a fire destroyed the records of this test except for the following partial document. Test of the mean battery the tablet Is the result significant at the 5% level? Is the result significant at the 2.5% level? Sample mean (hours) Sample size, n Yes No 11.8 Given that the population of battery lives is normally distributed with standard deviation 1.6 hours, find the set of possible values of the sample size, n. [5]

Read automatically from the paper; the printed page above is exact.