Assuming the data meets the assumptions of parametric tests, non-parametric tests compared to their parametric counterparts ____________.
Are more conservative
Have less statistical power
Are less likely to accept the alternative hypothesis
All of the above
A researcher measured leadership skills in doctors, police officers and accountants. The data were skewed. What is the most appropriate test to analyse the data?
Kruskal-wallis test
Friedman test
Wilcoxon test
Mann-whitney test
The results of the test used to analyze the data described in question 2 showed a significant result. How should the researcher carry out post-hoc tests?
Compare groups using Mann-whitney test
Compare groups using Wilcoxon test
Compare groups using t-Test
Non of the above. Post-hoc analyses can not be carried out with non-parametric data
An advantage of non parametric statistics is that ____________.
They are easy to calculate
They are very powerful
You need a computer to calculate them
They have many assumptions to meet
Which of the following tests is analogous to a standard within-subjects ANOVA?
Friedman
Kruskal-wallis
Wilcoxon
Mann-whitney
Tied scores (when two or more scores have the same value) may present a problem in non-parametric tests. The way to deal with them in a Kruskal-Wallis test is to
Throw out the tied data
Assign any tied values the lower of the ranks they would have recieved had they not been tied
Use a random number table to assign ranks to the tied values
Assign any tied values the average of the ranks they would have recieved had they not been tied
A data-set contains the following values: 23, 28, 37, 23, 45, 49, 37, 62. Rank the values. Which rank is associated with value 37?
4
4.5
3.5
6
Researchers wanted to examine whether the 'sea-food' diet was effective. A group of volunteers were placed on the diet and their weight (in kilograms) was measured at the beginning of the diet, after 1 month, after 2 months, then at the end of the diet after 3 months. The data were not normally distributed. Which test would be appropriate to analyse the data?
Kruskal-Wallis
Mann-Whitney
The output from the study described in question 8 is shown below. What is the correct way to report these results?
The weight of the participants did not significantly change during the diet, x2 (3) = .60, p = .89
The weight of the participants did significantly changed during the diet, x2 (3) = .60, p > .05
The weight of the participants did not significantly change during the diet, x2 (3) = .60, p = .90
The weight of the participants did significantly changed during the diet, x2 (3) = .60, p < .05
In a Kruskal-Wallis test, the ____________ the value of H, the more likely you are to reject the null hypothesis
More negative
Smaller
Larger
H is not relevant for the Kruskal-Wallis test
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