As part of a larger study of the effects of amphetamines, a pharmacologist wished to investigate the claim that amphetamines reduce overall water consumption. She injected 25 standard lab rats with an appropriate dose of amphetamine and 30 with a saline solution as controls. Over the next 24 hours she measured the amount of water consumed by each rat and expressed the results in ml/kg body weight: saline amphetamine
n 9 16
X 134.1 112
s 16 35.6
Does the amphetamine significantly suppress water consumption? What is the null hypothesis?
a. x-saline = X-amphetamine
b. mu-saline = mu-amphetamine
c. x-saline < X-amphetamine
d. mu-saline