Life tests performed on a sample of 13 batteries of a new model indicated: (1) an average life of 75 months, and (2) a standard deviation of 5 months. Other battery models, produced by similar processes, have normally distributed life spans. The 98% confidence interval for the population mean life of the new model is _________.

63.37 to 86.63

71.28 to 78.72

61.60 to 88.41

71.77 to 78.23

79.86 to 81.28