Question

Decide which type of analysis should be used to compare the groups in each of the following studies. Choose from: T-test for two non-independent sample means; ANOVA; MANOVA; & Mann-Whitney . Explain your answers in well constructed sentences.

a) Three 100-person groups were compared with regard to post-exercise heart rate. The groups were exposed to light, moderate and strenuous exercise, respectively.

b) Two 50-patient groups were compared with regard to mean blood pressure before and after a diet intervention. The groups were matched on age, gender, income, education level, race, and history of high blood pressure.

c) Two groups of randomly selected students in a medical ethics class were surveyed to compare average hours of sleep per night with class performance. Each group was composed of 14 students.

d) Three 100-person groups were compared with regard to post-exercise heart rate and lung function. Again, these groups were exposed to light, moderate and strenuous exercise, respectively.

Answer 1

a) ANSWER: ANOVA ( Analysis of variance for one way classification (F test))

Here Heart rate is quantitative variable and there are three groups. Now we are testing the mean difference between three groups. In this case we have to apply Analysis of variance test.

ANOVA is a technique used to test equality of several means.

b) ANSWER: t- Test for two non independent sample means ( Paired t test or dependent sample t test).

Here Blood pressure is a quantitative variable and it is measured of before and after the diet intervention. So we have to use t- Test for two non independent sample means.

The objective of t- Test for two non independent sample means is to test the mean difference between of before and after the treatment.

c) ANSWER: Mann-Whitney test .

Here the data is related to sleeping hours with class performance, and only two groups are there. This data is related to grades and hours. So we have to use non-parametric test.

d) ANSWER: MAANOVA.

Here there are two dependent variables.So we have to use Multivariate analysis variance procedure.

It is a procedure for comparing multivariate sample means.As a multivariate procedure, it is used when there are two or more dependent variables.