Scientists studying a particular species of endangered primate are concerned that the health of the primates is in danger due to habitat loss and malnutrition. Even the slightest decrease in average body weight is of great concern. Last Spring, each of the remaining members of the species were examined, and general information was recorded such as weight. It was found that the primate weights approximated a normal distribution. We randomly select a single sample member from the population and use its weight to represent the research population.

1. Assume our question of interest is: has there been a significant

decrease

in primate weights since

the last examination period (last Spring)? What type of test should be conducted?

a) one-tailed hypothesis test, rejection region at low tail

b) one-tailed hypothesis test, rejection region at high tail

c) one-tailed hypothesis test, directionality unknown

d) two-tailed hypothesis test