Antidepressants. A study compared the effectivenessof

Chapter 7, Problem 16

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Antidepressants. A study compared the effectivenessof several antidepressants by examining the experimentsin which they had passed the FDA requirements. Each ofthose experiments compared the active drug with aplacebo, an inert pill given to some of the subjects. Ineach experiment some patients treated with the placebohad improved, a phenomenon called the placebo effect.Patients depression levels were evaluated on the Hamil-ton Depression Rating Scale, where larger numbers indi-cate greater improvement. (The Hamilton scale is awidely accepted standard that was used in each of the in-dependently run studies.) The scatterplot at the top of thenext column compares mean improvement levels for theantidepressants and placebos for several experiments. a) Is it appropriate to calculate the correlation? Explain.b) The correlation is 0.898. Explain what we have learnedabout the results of these experiments.