Body temperatures were obtained from a sample of 60 intertidal crabs exposed to air at temperature between 25.5C and 26C. The mean body temperature from the sample is

25.8 C with a standard deviation of 1.7 C .

( a ) At the significance level of 1%, test the hypothesis that the mean body temperature of

this species of crab is below 26C using the critical value approach.

( b ) Test the hypothesis that the mean body temperature of this species of crab is above

25.5C using the p-value approach and a 5% level of significance.