#1 A test engineer wants to estimate the
mean gas mileage (in miles per gallon) for a
particular model of automobile. Eleven of
these are subjected to a road test, and the
gas mileage is computed for each car. A
dotplot of the 11 gas-mileage values is
roughly symmetrical and has no outliers. The
mean and standard deviation of these values
are 25.5 and 3.01, respectively. Assuming
that these 11 automobiles can be considered
a simple random sample of cars of this
model, what is the critical value for a 95%
confidence interval?