Battery Packs in Radio-Controlled Racing Cars Need to Be Able

Multiple Choice

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  = 2.5 hours.A simple random sample of 75 battery packs results in a mean of = 29.6 hours.What is a 90% confidence interval for ,the true average lifetime of the battery packs made by Lectric Co.?

A) (29.13,30.07)
B) (29.03,30.17)
C) (28.86,30.34)
D) The confidence interval cannot be calculated because the population distribution is not Normal.