Putting It Together: Online Homework Keeping students engaged in the learning process greatly increases their chance of success in a course. Traditional lecture-based math instruction has given way to a more student-engaged approach where students interact with the teacher in class and receive immediate feedback to their responses. The teacher presence allows students, when incorrect in a response, to be guided through a solution and then immediately be given a similar problem to attempt. A researcher conducted a study to investigate whether an online homework system using an attempt—feedback— reattempt approach improved student learning over traditional pencil-and-paper homework. The online homework system was designed to increase student engagement outside class, something commonly missing in traditional pencil-and-paper assignments, ultimately leading to increased learning.The study was conducted using two first-semester calculus classes taught by the researcher in a single semester. One class was assigned traditional homework and the other was assigned online homework that used the attempt—feedback—reattempt approach. The summaries are based on data from the study.


d. Explain why assigning homework type to entirely separate classes can confound the conclusions of the study.

Verified step by step guidance

1. Step 1: Understand the concept of confounding variables in an experiment. A confounding variable is an outside influence that changes the effect of a dependent and independent variable, potentially leading to incorrect conclusions about the relationship between them.
2. Step 2: Recognize that in this study, the independent variable is the type of homework assigned (online attempt-feedback-reattempt vs. traditional pencil-and-paper), and the dependent variable is the measure of student learning or engagement.
3. Step 3: Note that assigning homework types to entirely separate classes means that each class experiences only one type of homework, but the classes themselves may differ in other ways (e.g., instructor style, class time, student demographics, prior knowledge). These differences can act as confounding variables.
4. Step 4: Explain that because the classes are different groups, any observed differences in learning outcomes might be due to these other class differences rather than the homework type alone, making it difficult to isolate the effect of the homework method.
5. Step 5: Conclude that to avoid confounding, the study should ideally use random assignment of homework types within the same class or control for class differences, so that the effect of homework type on learning can be more confidently determined.

Key Concepts

Confounding Variables

Confounding variables are factors other than the independent variable that may affect the outcome of a study. When groups differ in ways besides the treatment, it becomes unclear whether observed effects are due to the treatment or these other factors. In this study, differences between the two classes besides homework type could confound results.

Experimental Design and Randomization

Experimental design involves planning how to assign treatments to subjects to ensure valid conclusions. Randomization helps evenly distribute unknown factors across groups, reducing bias. Assigning homework types to separate classes without randomization risks systematic differences influencing results.

Internal Validity

Internal validity refers to the degree to which a study accurately establishes a causal relationship between variables. If confounding factors or poor design exist, internal validity is compromised, making it difficult to attribute differences in learning outcomes solely to homework type.