Exam 1: An Introduction to Statistics and Research Design

In the famous Zimbardo prison study, Stanford students were assigned the role of either a prisoner or a guard so that the experimenters could examine prison life behaviors and interactions.The experiment was intended to run for two weeks but was stopped after only six days because of the brutal behavior of the guards and the depression of the prisoners.What was the independent variable in this study?

Confounding variables are connected to the dependent variable such that we cannot know which variable causes the effect we observe.

College students at 20 campuses around the country were polled to find out how many students own MP3 players.The number of MP3 owners at one campus represents a(n) _____ statistic.

A medical researcher interested in asthma symptoms wanted to know how symptoms were affected in dry versus humid conditions.The researchers recruited 18 asthma patients to spend four weeks under two conditions: sleeping with a dehumidifier for two weeks to create a "dry" environment and sleeping with a humidifier for the remaining two weeks to create a "humid" environment.Patients were asked to rate their symptoms at regular intervals using a scale from "0 - no symptoms" to "20 - maximum asthma symptoms." The change in asthma symptoms from dry to humid conditions was 5.82, showing a reduction of symptoms in humid conditions.What was the sample in this study?

A person's political affiliation is a(n) _____ variable.

A popular sports drink company sampled 20 people who drink its product regularly and found that they performed better during a physical test than did those who do not drink the product regularly.What might be a possible confound in the study?

There are three different types of Olympic medals: gold, silver, and bronze.Which variable describes the different types of Olympic medals?

A population is necessarily smaller than its respective sample.

Square footage, such as that used to describe home size, is a ratio variable.

In a between-groups research design, a participant experiences more than one of the levels of the independent variable.

A researcher was interested in assessing whether a new medication had negative side effects on reaction time.He performed an experiment on a group of rats.One group of rats received the medication, and the other group of rats did not.The researcher then measured reaction time differences between the two groups on a series of tasks.In this experiment, the independent variable is:

A researcher wants to assess well-being among dog and cat owners.She administers a well-being assessment to 125 dog owners and 163 cat owners.What type of research design is being used?

A weight-management researcher was interested in whether the size of breakfast could deter overall food consumption throughout the rest of the day.He creates two breakfast groups, a 350-calorie breakfast and a 750-calorie breakfast, assigns six participants to each group, and tracks their total calories eaten in one day.Because of the detailed attention needed to accurately interview participants about their eating, he works with the high-calorie group and has his assistant interview the low-calorie group.What is the dependent variable in this study?

Why does random assignment help control for confounding variables?

Random assignment refers to a situation in which:

Prof.Martin was interested in which of two popular statistics textbooks (Statistics: It Will Change Your Life and Statistics: Bigger, Better, Stronger) was better for students.Prof.Martin compared the two texts by assigning one text to a section of statistics taught by Prof.Miller from 10 to 11 a.m.on Monday, Wednesday, and Friday, and the other text to a section of statistics taught by Prof.Mervin from 7 to 10 p.m.on Wednesday evenings.At the end of the term, all students took the same comprehensive test.Students to whom Statistics: Bigger, Better, Stronger was assigned performed better on the test than did students to whom Statistics: It Will Change Your Life was assigned.Therefore, Prof.Martin concluded that the former textbook was the better one.What was the dependent variable in this study?

An elementary school teacher is interested in the relation between sugar consumption and activity level in preschool children.The teacher gives 30 preschool children from Preppy Preschool Playland 0 milligrams, 20 milligrams, or 50 milligrams of sucrose (sugar) in a breakfast drink.She then observes their behavior for 30 minutes during their morning outdoor play period and codes their activity level.In this example, the independent variable is:

A researcher was interested in assessing whether a new medication had negative side effects on reaction time.He performed an experiment on a group of rats.One group of rats received the medication, and the other group of rats did not.He then measured reaction time differences between the two groups on a series of tasks.In this experiment, the dependent variable is:

Which variables are always discrete?

Hsee and Tang (2007) reported the results of a study in which 195 college students completed a happiness scale (from 1 to 7) just before taking a midterm exam.On this scale, 1 corresponded to very unhappy and 7 to very happy.On average, the students rated their happiness as 6.18.In this study, which of these would require an inferential statistic?