If these assumptions are not met, there is likely to be a different statistical test that you can use instead. However, you should check whether your study meets these two assumptions before moving on. You cannot test the first two of these assumptions with Minitab because they relate to your study design and choice of variables.
The Wilcoxon signed-rank test has three "assumptions". However, before we introduce you to this procedure, you need to understand the different assumptions that your data must meet in order for a Wilcoxon signed-rank test to give you a valid result.
HYPOTHESIS TEST MINITAB HOW TO
In this guide, we show you how to carry out a Wilcoxon signed-rank test using Minitab, as well as interpret and report the results from this test. Alternately, you could use a Wilcoxon signed-rank test to understand whether there is a difference in productivity based on whether packers in a factory listen to background music (i.e., the dependent variable would be "productivity", measured in terms of the number of parcels packers processed per day, and the two related groups would be the two different "conditions" participants were exposed to that is, the number of parcels processed when packers listen to background music (condition A) compared to the number of parcels processed when packers do not listen to background music (condition B)). As the Wilcoxon signed-ranks test does not assume normality of the differences of the two related groups, it can be used when this assumption has been violated and the use of the paired t-test is inappropriate.įor example, you could use a Wilcoxon signed-rank test to determine whether there is a difference in the number of customer complaints before and after a training course for sales reps designed to improve their customer interactions (i.e., the dependent variable would be “customer complaints”, and the two related groups would be the two different “time points” that is, the number of customer complaints “before” the training course and the number of customer complaints “after“ the training course. It is the nonparametric equivalent to the paired t-test. The Wilcoxon signed-rank test determines whether there is a statistically significant difference in the median of a dependent variable between two related groups. I do my work in SAS.Wilcoxon signed-rank test using Minitab Introduction The next piece would be identifying the samples or groups of samples contributing to the significance and you would need to talk to the folks at Minitab to find out if it is possible and if so how to proceed.Īs for running this kind of analysis – yes – many times. If Minitab can handle mx2 contingency tables you should get a chi-square value of 12.6 and the p-value should be. The table check would be group x smoker and the questions is the significance of the ratio of smokers to non-smokers.
Just to see if Minitab can run the first part try this sample problem (from Fleiss pp.189) If that statistic is significant then the second part consists of the calculations needed to identify the proportions contributing to the significant difference. The first part of this kind of analysis is running a chi-square test on an mx2 contingency table. I don’t know Minitab so I can’t comment on its capabilities, however, my guess would be that it can do this – at least the first part anyway.
0 kommentar(er)
