Dr. Ramos is interested in studying how indoor temperature can influence people’s sleep quality during the summer. A sample of 100 households is selected in which the residents keep their houses at 76 degrees during the summer. The residents wear a monitoring device that measures their sleep cycles for several nights to get baseline readings. Then, 50 of the homes are randomly assigned to the warm temperature condition in which the residents agree to keep their houses at 82 degrees Fahrenheit. In the other 50 houses, the residents agree to keep their houses at 70 degrees. For several nights, Dr. Ramos collects the sleep data for the people living in the houses to see how the residents’ sleep patterns have changed. Assuming that the study allows people to use as many or as few blankets

as they like, number of blankets would be a(n) ____ variable in the experiment

a. correlational
b. extraneous
c. independent
d. dependent

Ans: b. extraneous