Does Sleep Affect Test Grades

Does the # of sleep affect test grades? Hypothesis: The amount of sleep will affect test grades. Materials and Procedures
The materials needed to conduct this experiment are:
-A group of students
-The same type of test
-Time
To start off this experiment, you must get a group of students and ask them individually the number of hours they slept. The number of hours they’ve slept will be the independent variable. Next, have the group of students take the same test and record their performance on the test. The test scores will be the dependent variable. Data Collected
Amount of Sleep Test Score
18 49
19 60
20 38