Researchers are interested in the mean age of a certain population. A random sample of 10 individuals drawn from the population of interest has a mean of 27.

a) Assuming that the population is approximately normally distributed with variance 20,can we conclude that the mean is different from 30 years ? (=0.05) .

b) If the p - value is 0.0340 how can we use it in making a decision

c) Referring to example above, Suppose that the researchers have asked: Can we conclude that < 30