An improper signi?cance test
A friend has performed a signi?cance test of the null hypothesis that two means are equal. His report states that the null hypothesis is rejected in favor of the alternative that the ?rst mean is larger than the second. In a presentation on his work, he notes that the ?rst sample mean was larger than the second mean and this is why he chose this particular one-sided alternative.
(a) Explain what is wrong with your friend's procedure and why.
(b) Suppose he reported t = 1.70 with a P-value of 0.06. What is the correct P-value that he should report?