Persons having Raynaud's syndrome are apt to suffer a sudden impairment of blood circulation in fingers and toes. In an experiment to study the extent of this impairment, each subject immersed a forefinger in water and the resulting heat output (cal/cm2/min) was measured. For m = 8 subjects with the syndrome, the average heat output was x = 0.62, and for n = 8 nonsufferers, the average output was 2.05. Let ΞΌ1 and ΞΌ2 denote the true average heat outputs for the sufferers and nonsufferers, respectively. Assume that the two distributions of heat output are normal with Ο1 = 0.3 and Ο2 = 0.4.
(a) Consider testing H0: ΞΌ1 β ΞΌ2 = β1.0 versus Ha: ΞΌ1 β ΞΌ2 < β1.0 at level 0.01. Describe in words what Ha says, and then carry out the test.
Ha says that the average heat output for sufferers is more than 1 cal/cm2/min below that of non-sufferers.
Calculate the test statistic and P-value. (Round your test statistic to two decimal places and your P-value to four decimal places.)
State the conclusion in the problem context.
(b) What is the probability of a type II error when the actual difference between ΞΌ1 and ΞΌ2 is ΞΌ1 β ΞΌ2 = β1.4? (Round your answer to four decimal places.)
(c) Assuming that m = n, what sample sizes are required to ensure that Ξ² = 0.1 when ΞΌ1 β ΞΌ2 = β1.4? (Round your answer up to the nearest whole number.)