Practicum: Music to my Ears

Practicum: Music to My Ears

Objective

You will design a simple experiment.

Note: Before you begin this practicum you will be engaging in a class discussion about experiments. Run through the questions in the boxes below as a guide for the discussion. Click to check your answers.

When is random assignment used? Why is it important?

Random assignment is used when you wish to determine whether a treatment causes changes in an outcome variable. It’s important because it creates a “balance” of the groups so that the only way the groups differ, on average, is that one gets the treatment and one does not. Thus, if there is a change in the outcome variable, only the treatment could have caused it.

Why is a control group important?

The control group is important because it allows us to measure the effects of the treatment group with an untreated comparable group. Without the control group, we don't know what would have happened if we had done nothing. Think of a new vaccine for the flu. If there is no control group and we see the treatment group improving, we will never know if they would have improved anyways, without the vaccine.

Below are some headlines. Your task is to determine if they are causal or not. If a headline is not causal, rewrite it so that it is. If causal, state why it’s causal. Click to check your answers.

Straight A’s in high school may mean better health later in life.

Not causal

Murder rates affect IQ test scores: Study.

Causal

Microbe linked to Alzheimer’s Disease.

Not causal

Luckiest people “born in summer”.

Not causal

Instructions

1. In class you designed and conducted the Time Perception experiment to find out if a person’s perception of time changed when exposed to a stimulus. This experiment was designed so that it used random assignment, which is the process of using a chance device (e.g., dice, RStudio, etc.) to determine the placement of subjects into the treatment and control groups. By randomizing, you are removing other possible explanations for why the results happened the way they did.

2. Using the Music to My Ears handout, you will be designing an experiment to determine whether doing math homework with music playing in the background affects students' test scores.

   Click on the document name to download a fillable copy of the Music to My Ears practicum.

Task

Work with your team to design this experiment. Submit a paper that clearly lays out your team’s design plan. Be sure to include:

1. Descriptions of each element of the experiment by answering the following questions:

   a. What is the research question we are interested in addressing?

   b. Who are the subjects that would be participating in the experiment? How should we select them?

   c. What could be possible treatments? What treatment do you choose and why? What will the control group do in your study?

   d. Describe how to randomize the subjects into the treatment and control groups.

   e. What is the outcome variable that we are measuring? Is it categorical or numerical? What other variables will you measure for each subject?

2. An analysis plan:

   a. What statistical questions will you ask to address your research question?

   b. What analyses (graphical and numerical) will you use to answer these questions?

   c. An explanation of how you will determine whether the treatment affects test scores.