
Copyright © 2007 Pearson Education, Inc Publishing as Pearson Addison-Wesley.Ħ Handling Ties in Ranks Find the mean of the ranks involved and assign this mean rank to each of the tied items. page of Elementary Statistics, 10th Edition Copyright © 2007 Pearson Education, Inc Publishing as Pearson Addison-Wesley.Įxplanation of efficiency values are in the middle of page 677 of Elementary Statistics, 10th Edition. Nonparametric tests are not as efficient as parametric tests, so with a nonparametric test we generally need stronger evidence (such as a larger sample or greater differences) before we reject a null hypothesis. Nonparametric methods tend to waste information because exact numerical data are often reduced to a qualitative form.

page 676 of Elementary Statistics, 10th Edition Copyright © 2007 Pearson Education, Inc Publishing as Pearson Addison-Wesley.ġ.

Nonparametric methods usually involve simpler computations than the corresponding parametric methods and are therefore easier to understand and apply. Unlike parametric methods, nonparametric methods can often be applied to categorical data, such as the genders of survey respondents. In particular, nonparametric methods do not require normally distributed populations. Nonparametric methods can be applied to a wide variety of situations because they do not have the more rigid requirements of the corresponding parametric methods. Consequently, nonparametric tests are called distribution-free tests. Nonparametric tests do not require that samples come from populations with normal distributions or have any other particular distributions. First Semester/2019Ģ Overview Definitions Parametric tests have requirements about the nature or shape of the populations involved. Yunes Mogheir Civil and Environmental Engineering Dept. Islamic University of Gaza Statistics and Probability for Engineers (ENGC 6310) Lecture 9: Nonparametric Statistics Prof. 1 Nonparametric Statistics Civil and Environmental Engineering Dept.
