3. A research study was conducted to determine if temperature determines activity level. Researchers observed a neighborhood park on three different days. The first day the temperature was 60 degrees, and the observation took place at nine o'clock in the morning. The second day the temperature was 70 degrees, and the observation took place at one o'clock in the afternoon. The third day was 80 degrees, and the observation took place at four o'clock in the afternoon. The researchers noticed there was more activity on the 70-degree day than on the other two days. Which of the following is not an error in the conduction of this study?
Confounding was found.
There was no independent variable.
Variables were not constant.
Controlled variables were not controlled.
