A friend has performed a significance test of the null hypothesis that two means
ID: 3243224 • Letter: A
Question
A friend has performed a significance test of the null hypothesis that two means equal. His report states that the null hypothesis is rejected in favor of the alternative that the first mean is larger than the second. In a presentation on his work, he notes that the first sample mean was larger 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. The null hypothesis in this case should have been that the first mean is larger than the second. The first mean can never be larger than the second mean: this indicates a mistake was made during statistical analysis. We should only choose a one-sided alternative if we have some reason to expect a specific directional outcome before looking at the sample results. The null hypothesis in this case should have been that the two means were not equal. We should never choose a one-sided alternative. (b) Suppose he reported t = 1.75 with a P-value of 0.06. What is the correct P-value that he should report?Explanation / Answer
(a) OPtion C is correct here as the friend should use two sided test because we are not heading for any perticular direction.
(b) t value = 1.75 and p - value = 0.06
The correct value he should report is 2 * p- value = 2 * 0.06 = 0.12 as it is two sided Test.