Question

A recent study of $1000$students at the University of Michigan investigated how to prevent catching a common cold. The students were randomly assigned to three different cold prevention methods for $6$weeks. Some wore masks, some wore masks and used hand sanitizer, and others took no precautions. The two groups who used masks reported $10–50\%$fewer cold symptoms than those who did not wear a mask.

a. Does this study allow for inference about a population? Explain your answer.

b. Does this study allow for inference about cause and effect? Explain your answer.

Short answer

a. The answer is No, the $1000$students were not randomly selected from a larger population.

b. The answer is yes, the subjects were randomly assigned to the three different cold prevention methods and there was a control group, thus the study then allows for inference about cause and effect.

Step-by-step solution

Part (a) step 1: Given Information

We need to explain the study to allow for inference about a population.

Part (a) step 2: Explanation

Here,

No, the $1000$students were not randomly selected from a larger population.

Part (b) step 1: Given Information

We need to explain the study to allow for inference about cause and effect.

Part (b) step 2: Explanation

An experiment deliberately imposes some treatment on individuals in order to observe to responses.

Since treatments were assigned to the students, the study was an experiment and experiments allow for inference about causes and effects when the subjects were randomly assigned to the treatment groups and there was a control group.

We note that the subjects were randomly assigned to the three different cold prevention methods and there was a control group, thus the study then allows for inference about cause and effect.