Sugar-free gum contains 40% less calories than regular gum. if a piece of regular gum contains 40 calories , how many calories does a piece of sugar-free gum contain?

Summary statistics given for independent simple random samples from two populations. use the pooled t-interval procedure to obtain specified confidence interval. x1=71.6, s1=3.9, n1=11, x2=67.9, s2=3.4, n2=9 determine a 99% confidence level.