A manufacturer reports that the mean lifetime of its lithium batteries is 1100 hours, but there are customer complaints that the battery life is lower. A consumer advocate group selects 25 of these batteries at random and finds the mean lifetime to be 1080 hours with a standard deviation of 80 hours. The sample data are approximately symmetric and unimodal with no outliers. Check conditions, show how the test statistic is calculated. Test using a 10% significance level. State your conclusion in the context of the problem.