The lengths of a random sample of 120 limpets taken from the upper shore of a beach hada mean of 4.97 cm and a standard deviation of 0.42 cm. The lengths of a second randomsample of 150 limpets taken from the lower shore of the same beach had a mean of5.05 cm and a standard deviation of 0.67 cm.
(a) Test, using a 5% level of significance, whether or not the mean length of limpets fromthe upper shore is less than the mean length of limpets from the lower shore. Stateyour hypotheses clearly.
(b) State two assumptions you made in carrying out the test in part (a).