Exam 17: Chi-Square and Other Nonparametric Tests

To answer this question, refer to the following data. Assume the data are being analyzed with the Mann-Whitney U test. The conclusion using a = 0.05_{2 tail} is _________.

The Mann-Whitney U test uses both the magnitude and direction of the scores.

The statistics used for the Mann-Whitney U test measure _________.

In an independent groups experiment, four wines are rated by individuals according to taste preference. The resulting data are shown below. The rating scale is from 1 to 20, with 20 representing the highest possible score. Assume the data preclude use of parametric ANOVA because of assumption violations. Analyze these results using an alternative test. a. What test will you use? b. Using a = 0.05, what is your conclusion?

U = 0 indicates the greatest degree of separation between the groups.

The data must be at least interval in scaling to use the Mann-Whitney U test.

The c 2 distribution is a family of curves that vary with degrees of freedom.

If U obt and U' obt are equal, there is little overlap between the groups.

For a low value of df the c 2 distribution is _________.

In Chapter 16, we presented the data from an independent groups design and asked if it was appropriate to use parametric ANOVA. The data are presented again below. The correct answer was that it was not appropriate to use parametric ANOVA because of unequal n s and homogeneity of variance assumption violation. Is it possible to analyze the data with an alternate test?

To use the Mann-Whitney U test, n 1 must equal n 2 .

As a general rule an investigator should use parametric tests whenever possible to help minimize the probability of making a Type II error.

Using c 2 , the closer the observed frequency of each cell is to the expected frequency for that cell, the higher the probability of rejecting H 0 .

What are the assumptions underlying the Mann-Whitney U test?

In analyzing the data from a two-way contingency table, involving variables A and B, what is the null hypothesis. Be specific using variables A and B, and the terms "proportions", frequency, and independent.

The following data were collected in an independent groups experiment to test the effect of different levels of a drug on blood pressure (mmHg). Assume the data seriously violate the assumptions underlying parametric ANOVA. Therefore, you will have to use an alternative test to analyze the data. a. What test will you use? b. What is your conclusion? Use a = 0.01

A study is conducted to determine whether sunshine affects depression. Eight individuals are given a questionnaire measuring depression immediately following a run of 10 consecutive days when the sun shone for over 80% of the daylight hours. The same individuals have their depression measured immediately following 10 consecutive days without any sunshine. The following data are collected. The higher the score the greater the depression. Using the Wilcoxon signed ranks test to evaluate the data, the value of T obt is _________.

In any specific case f o - f e should equal zero if H₀ is true.

The Wilcoxon signed ranks test _________.

A study is conducted to determine whether sunshine affects depression. Eight individuals are given a questionnaire measuring depression immediately following a run of 10 consecutive days when the sun shone for over 80% of the daylight hours. The same individuals have their depression measured immediately following 10 consecutive days without any sunshine. The following data are collected. The higher the score the greater the depression. Using the Wilcoxon signed ranks test to evaluate the data, with a = 0.05 2 tail , T crit = _________.