As treatment for panic disorder,_________may produce dependence; most patients experience a relapse when medications are discontinued.

A researcher would like to test the claim that 9 out of 10 doctors prefer Brand X. A sample of 60 doctors is obtained and each is asked to compare Brand X with another leading brand. The data show that 48 of the doctors picked Brand X. If these data are evaluated using a chi-square test for goodness of fit, what is the expected frequency for Brand X?

a. 6 c. 48 b. 12 d. 54

Dr. Fowler is interested in studying how indoor lighting can influence people's moods during the winter. A sample of 100 households is selected. Fifty of the homes are randomly assigned to the bright-light condition where Dr. Fowler replaces all the lights with 100-watt bulbs. In the other 50 houses, all the lights are changed to 60-watt bulbs. After two months, Dr. Fowler measures the level of

depression for the people living in the houses. In this study, the independent variable is the ____. a. brightness of the lights b. level of depression c. houses with 100-watt bulbs d. houses with 60-watt bulbs