A researcher wants to determine the effects of sleep on memory and decides to schedule two groups of subjects for a sleep study. Both groups will be asked to memorize as many items as they can from the same prepared list of items. Then they will be allowed to go to sleep. In group A, the subjects will only be allowed to sleep for six hours. In group B, the subjects will be allowed to sleep for their usual amount of time. After each subject is finished sleeping, a quiz will be given over the list that was supposed to be memorized. What is the independent variable in the experiment? A. amount of sleep B. group B subjects C. memory D. group A subjects

In research, there are two main types of variables the dependent and the independent variable. The dependent variable refers to the factor or situation that is being studied by the research and therefore cannot be controlled by it. On the other hand, an independent variable is a variable the researcher modifies or controls in order to understand or study the dependent variable. This means while the dependent variable is the one that cannot be controlled and whose results answer the question of the research the independent variable is the factor control by the research and that varies according to the groups the researcher is studying.

Considering this, if the researcher wants to know the effects of sleep on memory and for doing this it gives two different groups of subjects the same lists to memorize, but different time to sleep the dependent variable is the memory and the list as it is the same for all the subjects and the independent variable, in this case, is the amount of sleep as this is the factor controlled by the researcher.