Chapter 1: Study Guide

List and describe the steps in the process of science.

- Observation: read peer reviewed journals and study published articles/journals/research. - Question: ask a question that could be solved through experimentation. - Hypothesis: predict a possible answer to the question being asked. - Experiments: test your hypothesis. - Data: track your data for proving/disapproving your hypothesis; share your data with others and continue testing theory. - Conclusions: share your results, as well as have them peer reviewed after intensive research and experimenting.

Experiment

A carefully designed test, the results of which will either support or rule out a hypothesis.

Correlation

A consistent relationship between two variables.

Randomized Clinical Trial

A controlled medical experiment in which subjects are randomly chosen to receive either an experimental treatment or a standard treatment (or a placebo).

Placebo

A fake treatment given to control groups to mimic the experience of the experimental groups.

Statistical Significance

A measure of confidence that the results obtained are "real" not due to chance.

Peer Review

A process in which independent scientific experts read scientific studies before they are published to ensure that the authors have appropriately design and interpreted the study.

Hypothesis

A tentative explanation for a scientific observation or question.

You wish to test the effects of energy drinks on short-term memory in college students. You recruit 100 volunteers for your study. The control group will receive a placebo, and the experimental group, the same volume of Red Bull. You will administer a test of short-term memory 30 minutes after participants consume their drinks. In your study, the independent variable and dependent variable are (in that order): A. Red Bull/performance on the short-term memory test. B. performance on the short-term memory test/Red Bull. C. performance on the short-term memory test/placebo. D. placebo/performance on the memory test.

A. Red Bull/performance on the short-term memory test.

In one study, a researcher found that people who were below 5 feet 5 inches in height were relatively unlikely to have red hair. This is an example of A. correlation. B. causation.

A. correlation.

Scientific Theory

An explanation of the natural world that is supported by a large body of evidence and has never been disproved.

Anecdotal Evidence

An informal observation that has not been systematically tested.

You wish to test the effects of energy drinks on short-term memory in college students. You recruit 100 volunteers for your study. The control group will receive a placebo, and the experimental group, the same volume of Red Bull. You will administer a test of short-term memory 30 minutes after participants consume their drinks. Should the control group know that it is receiving the placebo? A. Yes, so you avoid a placebo effect. B. No, so you can avoid a placebo effect. C. Yes, because it is the independent variable. D. No, but the experimental group should know it is receiving the energy drink. E. It doesn't matter; the results will not be affected either way.

B. No, so you can avoid a placebo effect.

In a scientific experiment, which group would typically receive a placebo treatment? A. experimental group B. control group C. everyone involved in the study

B. control group

"I feel more cheerful when I wear bright clothing; therefore, bright clothing makes people more cheerful" is an example of a(n) (choose all correct answers) A. scientific theory. B. everyday theory. C. hypothesis. D. data.

B. everyday theory. C. hypothesis.

Your aunt told you that she is going to change her brand of breakfast cereal to one that is higher in vitamin E. She has based her decision on a news report of a scientific study finding that adults who ate vitamin E-fortified cereal had better cardiovascular health than did those who ate other kinds of cereal. You are skeptical, so you track down the original scientific article and discover that the sample size for the study was five individuals. What do you tell your aunt? A. She should definitely change her cereal based on the strength of the study. B. She should definitely not change her cereal because the study's sample size was too small. That means she should come to the conclusion opposite the one reported in the news. C. If she changes her cereal, she should not expect to see any changes in cardiovascular health. The sample size in the study is too small for its results to be reliable. D. She should change cereals because even though the sample size is too small for the study's conclusions to be reliable, she will benefit from a placebo effect. E. Both C and D are legitimate responses.

C. If she changes her cereal, she should not expect to see any changes in cardiovascular health. The sample size in the study is too small for its results to be reliable.

What is typically the order of the scientific process? A. question, observation, experiments, data, hypothesis, conclusions B. experiments, data, hypothesis, conclusions, question, observation C. observation, question, hypothesis, experiments, data, conclusions D. hypothesis, questions, experiments, data, conclusions

C. observation, question, hypothesis, experiments, data, conclusions

When reading media stories about scientific discoveries, I will A. believe everything that I read. B. believe what I want to think is real. C. base my acceptance or rejection of the conclusion on alignment of the planets. D. base my acceptance or rejection of the conclusion on the data in the original research paper and what I have learned in this class.

D. base my acceptance or rejection of the conclusion on the data in the original research paper and what I have learned in this class.

Falsifiable

Describes a hypothesis that can be ruled out by date that show that the hypothesis does not explain the observation.

Testable

Describes a hypothesis that can be supported or rejected by carefully designed experiments or observational studies.

How did Dr. Ryan control for a placebo effect?

Dr. Ryan did not tell the control group they received decaffeinated coffee in the experiment.

You wish to test the effects of energy drinks on short-term memory in college students. You recruit 100 volunteers for your study. The control group will receive a placebo, and the experimental group, the same volume of Red Bull. You will administer a test of short-term memory 30 minutes after participants consume their drinks. Which of the following best describes how you would assign participants to your experimental and control groups? A. Assignment is completely random. B. Assignment is completely random if all volunteers regularly use energy drinks. If not, the ones who regularly use energy drinks are assigned to the control group and the rest to the experimental group. C. Assignment is random except for sex: each group must have an equal number of males and females. D. Assignment is random except for smoking status: each group must have an equal number of smokers and nonsmokers. E. These are all valid ways to assign participants to the two groups.

E. These are all valid ways to assign participants to the two groups.

Once a scientific hypothesis has been tested and supported by one scientist in one study: A. no more studies need be conducted; the hypothesis is now considered a fact. B. it has no value at all until it has been tested by at least three other scientists in independent investigations. C. no more studies need be conducted; as long as the study is published in a peer-reviewed journal, the scientific community will accept the hypothesis with great confidence. D. the same study must be repeated by the same scientist at least three times so that his/her results can be published. E. the same hypothesis must be tested in different ways by different researchers, both to refine it and to increase our confidence that it is the best explanation for the observations in question.

E. the same hypothesis must be tested in different ways by different researchers, both to refine it and to increase our confidence that it is the best explanation for the observations in question.

True or False: A question and a hypothesis are the same thing.

False.

Explain the statement, "correlation is not causation."

Just because two things correlate, does not mean that one causes the other. For example, just because those who drink coffee have a lower chance of Parkinson's Disease, does not mean coffee can prevent it. There are too many other factors to prove not drinking coffee is the cause of Parkinson's Disease.

What was the dependent variable?

The dependent variable is the subjects' memory/performance on the memory test.

How was the dependent variable measured? Was it measured differently in the control and experimental groups?

The dependent variable was measured by having the subjects complete the exact same memory test in the morning and in the afternoon, after drinking caffeinated/decaffeinated coffee. Both the control group and experimental group were measured the same.

How did Dr. Ryan make the independent variable different between the experimental and control groups (i.e., what "treatment" did the experimental group receive and what "treatment" did the control group receive)?

The experimental group received the normal amount of caffeine in a cup of coffee, while the control group received decaffeinated coffee as a placebo.

Which of the steps in the process should be repeated if the hypothesis in question is to be more rigorously tested? Explain.

The experimental process should be repeated rigorously to test the hypothesis and ensure that the outcome is not by chance.

Control Group

The group in an experiment that experiences no experimental intervention or manipulation.

Experimental Group

The group in an experiment that experiences the experimental intervention or manipulation.

What was the independent variable?

The independent variable in Dr. Ryan's study was coffee.

List the limitations of media reports that may prevent reporters from including all relevant details of a scientific study.

The limitations of media reports include not having enough space to fully explain the research conducted and/or difficulty making the research readable to the average person while also explaining its complex scientific data.

Dependent Variable

The measured result of an experiment, analyzed in both the experimental and control groups.

Sample Size

The number of experimental subjects or the number of times an experiment is repeated. In human studies, sample size is the number of participants.

Science

The process of using observations and experiments to draw conclusions based on evidence.

Epidemiology

The study of patterns of diseases in populations, including risk factors.

Independent Variable

The variable, or factor, being deliberately changed in the experimental group relative to the control group.

Explain why the conclusions based on a larger sample are more reliable than those based on a smaller sample.

When conclusions are based on smaller sample sizes, there is more room for results to be base upon chance rather than a "real" outcome.

List and describe some questions a skeptical consumer should ask about a media report before accepting the reported conclusions at face value.

Who conducted the study? What were the independent and dependent variables? What was the sample size? What was the age range, sex, and other individual factors of the test subjects? Has this report been peer reviewed? Is this correlation or causation?