Please help

Battery packs in radio-controlled racing cars need to be able to last pretty long. The distribution of the lifetimes of battery packs made by Lectric Co. is slightly left-skewed. Assume that the standard deviation of the lifetime distribution is 0-: 1.5 hours. A simple random sample of 85 battery packs results in a mean of 3c = 28.6 hours. a) What is a 95% confidence interval for y, the true average lifetime of the battery packs made by Lectric Co.? b) If a 99% confidence interval had been calculated, would the margin of error have been larger? Why or why not