In a Study on Effectiveness of Therapy in Treating Depression

question 47

Multiple Choice

In a study on effectiveness of therapy in treating depression, participants are randomly assigned to groups so that 10 receive cognitive behaviour therapy (CBT) and 10 are assigned to a no-treatment control condition. The outcome improvement scores for participants in the CBT group are quite different from each other (e.g., some had minimal improvement scores, while others showed large benefits) . This discrepancy is referred to as:

• A)The third variable problem
• B)The directionality problem
• C)Within-group variance
• D)Between-group variance

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Definitions:

Degrees of Freedom

The number of independent values or quantities which can be assigned to a statistical distribution, affecting the shape of the distribution.

P-values

P-values provide the probability of obtaining an effect at least as extreme as the one in your sample data, assuming the truth of the null hypothesis.

Standard Error

A statistic that measures the average distance that a sample statistic, such as the mean, deviates from the actual population mean.

Alternative Hypothesis

A statement that contradicts the null hypothesis and is tested directly in a hypothesis testing framework, assuming the null hypothesis is false.