Joey wants to see how the amount of TV watching affects grades. He surveys 100 high school students about the number of hours they watch TV during the week and also their grades. He makes sure that all the students he surveys are freshmen and go to the same class.
a.
: amount of TV watching
b.
: grades
c.
: students who are freshmen and go to the same class
d. Population: high school students
e. Sampling method: convenience sampling
f. Sample size: 100
g. Extraneous variables:
- Time management skills of students
- Study habits of students
- Physical health of students
- Family support and environment
- Prior academic performance of students
- Individual differences in learning abilities and styles
a. The independent variable in this study is the amount of TV watching. This variable is manipulated by Joey to see how it affects the dependent variable.
b. The dependent variable in this study is the grades of the high school students. This variable is measured to determine the outcome or effect of the independent variable.
c. The controlled variables in this study are the students who are freshmen and go to the same class. Joey ensures that all the students surveyed meet these criteria to control for any potential confounding factors that may influence the relationship between TV watching and grades.