Each car in a sample of seven cars was tested for nitrogen-oxide emissions

Each car in a sample of seven cars was tested for nitrogen-oxide emissions (in grams per mile), and the following results were obtained.

0.07
0.12
0.15
0.16
0.15
0.08
0.16
a. Assuming that this sample is representative of cars in use, construct a 95% confidence interval estimate of the mean amount of nitrogen-oxide emissions for all cars.