Chapter 4 - More Exp Vocab

Front

Double-blind experiment: subjects & doctors unaware of who takes which medication.

Back

Both subjects and doctors are unaware of who is taking which medication.

Answer explanation

A double-blind study is when the subjects and those who collect the data are both unaware of who is assigned to which treatment group.

Front

Researchers assigned over 1000 chronic back pain patients to traditional Chinese acupuncture, placebo acupuncture, or conventional treatment. What is the purpose of random assignment?

Back

To create groups that are as similar as possible so the main difference between the groups is the treatments.

Answer explanation

The goal of random assignment is to roughly balance other variables (age, gender, pain level, attitudes, and so on) between the treatment groups. This way, the main difference between the groups is the explanatory variable, so we can make comparisons.

Front

A professor studies a new tool's effectiveness for 150 students by ranking them and using a coin flip to assign tools. What type of experiment design is this?

Back

Matched pairs

Answer explanation

The subjects were first put into pairs with another similar student, and it was randomly determined which member of each pair used the new study tool and which one didn't, so this study used a matched pairs design.

Front

Impact of environmental sounds on ecosystems studied by Mississippi State University using 3 ecosystems exposed to rock music, country music, or city soundscape for 2 weeks.

Back

A completely randomized design.

Answer explanation

The 3 ecosystems were each randomly assigned a treatment. They were not grouped in any way with random assignment happening within each group, so this is a completely randomized design.

Front

A professor studies a new tool's effectiveness with 150 students. 75 use the new tool, 75 use the old. What type of experiment design is this?

Back

Completely randomized

Answer explanation

This study is an example of a completely randomized design since each subject is randomly assigned to one of the treatment groups without extra consideration to other variables.

Front

An insurance company studies if incentives for preventative care lower health costs using a sample of 200 customers, assigning smokers and nonsmokers to treatment and control groups. What type of experiment design is this?

Back

Randomized block

Answer explanation

Subjects were divided into groups based on smoking habits before being randomly assigned, so this study used a randomized block design.

Front

A footwear company tests new insoles for shin splints with 100 adults, using a double-blind design. Why use this design?

Back

It protects against some possible sources of bias.

Answer explanation

The blinding in the subjects protects against potential bias from the placebo effect.

Also, the blinding in the researchers protects against potential bias that could arise if researchers favor one type of insole over the other.

A double-blind design protects against some possible sources of bias.

Front

Footwear company tests new insoles for shin splints with 100 adults, comparing new vs existing insoles. Why might using no insoles for one group cause confounding?

Back

A difference between the two groups could be due to the placebo effect.

Answer explanation

People in an experiment will often respond to any treatment at all, even a treatment that has no real therapeutic value. This is known as the placebo effect.

So a group using any insoles may respond favorably compared to a group with no insoles.

This design might lead to confounding because a difference between the two groups could be due to the placebo effect.

Front

Purpose of random assignment in a study comparing new vs existing insoles for shin splints prevention.

Back

It tends to create roughly similar groups.

Answer explanation

Random assignment makes it unlikely that runners who have something in common will end up in the same group. For example, it would be very unlikely for every runner who is deficient in calcium to be assigned to the same group. This goes for other variables that might cause an imbalance in the groups that would directly effect whether runners get shin splints..

Random assignment creates roughly similar groups by approximately balancing potentially confounding variables between the two groups.

It tends to create roughly similar groups.

Front

Purpose of 50 runners using existing insoles?

Back

They serve as a control group.

Answer explanation

A comparative experiment involves one group receiving a treatment (the insoles) and another group that doesn't receive the treatment. The group that doesn't receive the treatment is called the control group.

The group of 50 runners using the existing insoles serves as a control group.