Nandy

The emission of 10 engines is found to be: 15.6, 16.2, 22.5, 20.5, 16.4, 19.4, 16.6, 17.9, 12.9, 13.9. The mean emission must, according to regulations, be u (mean) greater than 20 parts per million. Test this at a significance level of a equal to 0.01

They helps us to learn different types of living things around us.