3. The service life of a battery used in a cardiac pacemaker is assumed to be normally distributed. A sample of twelve batteries is subjected to an accelerated life test by running them continuously at an elevated temperature until failure, and the following lifetimes (in hours) are obtained: 25.5, 26.1, 26.8, 23.2, 24.2, 28.4, 25.0, 27.8, 27.3, 25.7, 26.5, and 24.8. Test the hypothesis that the mean battery life exceeds 25 hours. a) State the null and alternative hypothesis. b) Compute the test statistics. c) Compute the P-value. d) State a conclusion e) Construct a 95% two-sided confidence interval on mean life in the accelerated test