Answer:
independent variable: Amount of money ($20) offered to students
dependent variable: level of performance
control group: The group of students that were not offered any incentive
constant: same time given (15 minutes), same reading material
Explanation:
In an experiment, the independent variable is the variable that an experimenter manipulates or changes in order to effect a response. In this case the independent variable is the AMOUNT OF MONEY ($20) OFFERED TO STUDENTS
The dependent variable is the variable that responds to the changes made to the independent variable, hence, it is the measured variable. In this case, the dependent variable is the LEVEL OF PERFORMANCE
The control group in an experiment is the group that receives no experimental treatment or independent variable. In this case, the control group is the GROUP OF STUDENTS THAT WERE NOT OFFERED ANY INCENTIVE.
The constant or control variable is the variable that the experimenter keeps constant or unchanged for all the groups in order not to influence the outcome. In this experiment, the constants are SAME TIME GIVEN (15 minutes), SAME READING MATERIAL