Dr. nguyen is studying how amount of sleep influences mood for kindergarteners. a sample of 100 children is selected. fifty children are allowed to sleep for 11 hours each night. the other 50 children are awoken after 8 hours. after three nights, dr. nguyen records the mood for each child and compares the two groups of scores. in this example, how many levels are there for the independent variable?

The answer is 2 levels

Explanation:

There are two levels in this case because the experiment in question here compares how two sleep levels, which can be said to be the experimental sleep level of 11 hours, and the control sleep level of 8 hours. Basically the type of treatment provided in the question has two levels: control and experimental. This entails that if an experiment was designed to compare 4 types of meal, then such experiment can be said to have 4 levels of independent variables.