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1. You are conducting a study of three types of nutritional supplements for elde

ID: 3227517 • Letter: 1

Question

1. You are conducting a study of three types of nutritional supplements for elderly adults to test their effectiveness in producing weight gain (yes/no) within a 2 month period. You sample four groups of 10 adults (one is a control group receiving the usual diet, but no supplement). Select the appropriate statistical test to evaluate the null hypothesis that some nutritional supplements cause more weight gain than the usual diet in elderly adults.

answer on chegg says mann-whitney, the i just took said it was the wrong answer. Is my faulty or what is the answer ?

Explanation / Answer

Here the dependent variable is a binary variable (yes/no). As we dont have a continuous dependent variables so we can not use Anova test for multiple group comparisons. Mann-whitney u test is used for comparing only 2 groups. As we have 4 groups here, we can not use Mann-whitney u test. When we have more than 2 groups and we cant use Anova test, Kruskal-Wallis test can be used as an appropriate statistical test. In R, we can carry out kruskal-wallis test using kruskal.test() function.