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To determine if topiramate is a safe and effective treatment for alcohol dependence, researchers conducted a 14 -week trial of 371 men and women aged 18 to 65 years diagnosed with alcohol dependence. In this double-blind, randomized, placebo-controlled experiment, subjects were randomly given either 300 milligrams (mg) of topiramate (183 subjects) or a placebo (188 subjects) daily, along with a weekly compliance enhancement intervention. The variable used to determine the effectiveness of the treatment was self-reported percentage of heavy drinking days. Results indicated that topiramate was more effective than placebo at reducing the percentage of heavy drinking days. The researchers concluded that topiramate is a promising treatment for alcohol dependence. (a) What does it mean for the experiment to be placebocontrolled? (b) What does it mean for the experiment to be double-blind? Why do you think it is necessary for the experiment to be double-blind? (c) What does it mean for the experiment to be randomized? (d) What is the population for which this study applies? What is the sample? (e) What are the treatments? (f) What is the response variable?

Step by step solution

01

Title - Placebo-Controlled Experiment

In a placebo-controlled experiment, one group of participants receives the treatment (in this case, topiramate), while another group (the control group) receives a placebo. The placebo is an inactive substance designed to look like the actual treatment but has no therapeutic effect. This allows researchers to compare the effects of the treatment against no treatment to measure its true effectiveness.

02

Title - Double-Blind Experiment

A double-blind experiment means that neither the participants nor the researchers know who is receiving the treatment and who is receiving the placebo. This is important to prevent bias in the results and to ensure that the observed effects are due to the treatment itself and not influenced by participants' or researchers' expectations.

03

Title - Importance of Double-Blind

Double-blind procedures are necessary to maintain objectivity. If participants or researchers knew who was receiving the treatment, it could influence their behavior or evaluation of the outcomes, leading to biased results.

04

Title - Randomized Experiment

In a randomized experiment, participants are randomly assigned to either the treatment group or the control group. Randomization ensures that the groups are comparable and that the results are not influenced by external factors or inherent differences between the groups.

05

Title - Population and Sample

The population for which this study applies is all men and women aged 18 to 65 years diagnosed with alcohol dependence. The sample consists of the 371 men and women who participated in the 14-week trial.

06

Title - Treatments

The treatments in this experiment are the 300 mg dosage of topiramate and the placebo given to the participants.

07

Title - Response Variable

The response variable is the self-reported percentage of heavy drinking days. This variable is used to measure the effectiveness of topiramate in reducing heavy drinking among participants.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Placebo-Controlled Study

In a placebo-controlled study, participants are divided into two groups. One group receives the actual treatment (in this case, topiramate), and the other group receives a placebo. A placebo is an inactive substance that looks like the treatment but has no therapeutic effect.
This allows researchers to determine if the treatment has a real impact beyond psychological factors. By comparing the treatment group to the placebo group, researchers can measure the true effectiveness of the new treatment. The placebo-controlled design prevents participants' beliefs about the treatment from influencing the outcomes.

Double-Blind Study

A double-blind study ensures that neither the participants nor the researchers know who is receiving the treatment and who is receiving the placebo. This setup is crucial to minimize bias.

Here’s why double-blind studies matter:

• If participants knew they were getting the treatment, they might report better outcomes just because they expect the treatment to work.


• If researchers knew who was receiving the treatment, they might unintentionally influence the results through their interactions or evaluations.

This method helps in providing more reliable and objective results.

Randomized Control Trial

In a randomized control trial, participants are assigned to either the treatment group or the control group randomly. Randomization is used to ensure that the groups are comparable and that external factors do not influence the study's results.

Key benefits of randomization include:

• Reducing selection bias by ensuring each participant has an equal chance of being in either group.


• Balancing out unknown factors that could affect the results.

Randomization ensures the fairness and accuracy of the experiment's outcomes.

Response Variable

The response variable is the primary outcome that researchers are measuring in the study. It indicates the effectiveness of the treatment.

In this experiment, the response variable is the self-reported percentage of heavy drinking days. This measure helps in assessing whether the treatment (topiramate) reduces heavy drinking compared to the placebo.

Consistently tracking the response variable provides clear data on the impact of the treatment.

Sample vs Population

Understanding the difference between a sample and a population is fundamental in research.

The population refers to the entire group being studied. In this case, it includes all men and women aged 18 to 65 years diagnosed with alcohol dependence.

The sample is a smaller subset of the population that the researchers actually study. Here, the sample consists of the 371 participants in the 14-week trial.

Researchers use samples to make inferences about the broader population. By carefully selecting and studying a representative sample, they can draw conclusions that apply to the entire population.