A test engineer wants to estimate the mean gas mileage (in miles per gallon) for a particular model of automobile. Eleven of these cars are subjected to a road test, and the gas mileage is computed for each car. A dot plot 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, which of the following is a correct statement?
a. A 95% confidence interval for μ is 25.5 ±2.2284 3.01
b. A 95% confidence interval for μ is 25.5±2.201 3.01
c. A 95% confidence interval for μ is 25.5±2.228 10 3.01
d. A 95% confidence interval for μ is 25.5±2.201 10
e. The results cannot be trusted; the sample is too small.