Skip to main content
Ch. 1 - Introduction to Statistics
Larson - Elementary Statistics: Picturing the World 8th Edition
Larson8th EditionElementary Statistics: Picturing the WorldISBN: 9780137493470Not the one you use?Change textbook
All textbooksLarson 8th EditionCh. 1 - Introduction to StatisticsProblem 1.r.22
Chapter 1, Problem 1.r.22

200 students volunteer for an experiment to test the effects of sleep deprivation on memory recall. The students will be placed in one of five different treatment groups, including the control group.
Explain how you could design an experiment so that it uses a completely randomized design.

Verified step by step guidance
1
Define the experimental groups: Clearly identify the five treatment groups, including the control group. For example, the groups could represent different levels of sleep deprivation (e.g., 0 hours, 2 hours, 4 hours, 6 hours, and 8 hours of sleep).
Randomly assign participants: Use a randomization method (e.g., a random number generator or drawing lots) to assign each of the 200 students to one of the five groups. Ensure that each group has an equal number of participants, if possible, to maintain balance.
Control for confounding variables: Ensure that all other factors (e.g., age, gender, prior sleep habits) are evenly distributed across the groups by relying on the randomization process. This helps to isolate the effect of sleep deprivation on memory recall.
Administer the treatments: Implement the sleep deprivation conditions for each group as planned. For example, the control group might get 8 hours of sleep, while the other groups receive progressively less sleep.
Measure the outcome: After the treatment period, test all participants using the same memory recall test under identical conditions. Record and analyze the results to determine if there are significant differences in memory recall between the groups.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
3m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Completely Randomized Design

A completely randomized design is an experimental setup where all subjects are assigned to treatment groups purely by chance, ensuring that each participant has an equal opportunity to be placed in any group. This method helps eliminate bias and allows for a fair comparison of the effects of different treatments, as it minimizes the influence of confounding variables.
Recommended video:
Guided course
07:09
Intro to Random Variables & Probability Distributions

Random Assignment

Random assignment is the process of allocating participants to different treatment groups in a way that is determined by randomization, such as using random number generators or drawing lots. This technique is crucial in experimental design as it helps ensure that the groups are comparable at the start of the experiment, thus enhancing the validity of the results.
Recommended video:
Guided course
07:09
Intro to Random Variables & Probability Distributions

Control Group

A control group is a baseline group in an experiment that does not receive the treatment being tested, allowing researchers to compare the effects of the treatment against a standard. This group is essential for determining the effectiveness of the treatment, as it helps isolate the impact of the independent variable on the dependent variable, in this case, memory recall.
Recommended video:
Guided course
05:26
Creating Scatterplots - Graphing Calculator
Related Practice
Textbook Question

You want to know the favorite spring break destination among 15,000 students at a university. Determine whether you would take a census or use a sampling. If you would use a sampling, determine which sampling technique you would use. Explain your reasoning.

7
views
Textbook Question

Identify the sampling technique used, and discuss potential sources of bias (if any). Explain.

A student asks 18 friends to participate in a psychology experiment.

7
views
Textbook Question

Identify the sampling technique used, and discuss potential sources of bias (if any). Explain.

Law enforcement officials stop and check the driver of every third vehicle for blood alcohol content.

8
views
Textbook Question

Determine whether the study is an observational study or an experiment. Explain.

Researchers conduct a study to determine whether a medication based on fish oil known as omega-3 carboxylic acids is effective in reducing the risk of cardiac events in people already at risk. In the study, 13,078 patients are randomly chosen to receive either omega-3 carboxylic acids or a placebo of corn oil daily. Researchers compare the number of cardiac events of the two groups over similar follow-up periods of time. (Source: American Heart Association)

7
views
Textbook Question

200 students volunteer for an experiment to test the effects of sleep deprivation on memory recall. The students will be placed in one of five different treatment groups, including the control group.

Explain how you could design an experiment so that it uses a randomized block design.

7
views