A researcher finds that the number of positive ranks is 13 and the number of negative ranks is 4 using a sample of 17 participants.Based on these data,what is the decision for a related samples sign test at a .05 level of significance?
A)Retain the null hypothesis.
B)Reject the null hypothesis.
C)There is not enough information to answer this question.

Question

Quizplus · Accepted Answer

To conduct a related samples sign test, we test the null hypothesis that the median of the differences between the two related samples is zero. We count the number of positive and negative differences and use the binomial distribution to calculate the probability of getting the observed number of positive and negative ranks (or a more extreme result) if the null hypothesis is true. In this case, we have 13 positive ranks and 4 negative ranks, which gives a two-tailed p-value of 0.021. Since this p-value is less than .05, we reject the null hypothesis and conclude that there is evidence that the median of the differences is not zero.

A Researcher Finds That the Number of Positive Ranks Is