A friend has performed a significance test of the null hypothesis that two means
ID: 3218633 • Letter: A
Question
A friend has performed a significance 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 first mean is larger than the second, in a presentation on his work, he notes that the first sample mean was larger than the second mean and this is why he chaos 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 a been that the two means were not equal. The first mean can never be large than the second mean; this indicate 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. We should never choose a one sided alternative. The null hypothesis in this case should have been that the first mean is larger than the second. b) Suppose he report t = 1.45 with a P-value of 0.09. What is the correct P-value that he should report?Explanation / Answer
Solution:-
a) option c. 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.
b) p-value is 0.09*2 = 0.18