刚开始学用R，如何在R里写如下题目的code？
题目是两组数据，用t.test(one tailed) 比较the mean of group A > the mean of
group B.
下面的两个问题，该如何写呢?
1。 Find the power of this test for detecting an actual difference in means
of 2.5?
2. What sample size would be necessary to detect an actual difference in
means of 1.5 with a power of at least 0.9
非常感谢
