Question 1

To decide that the independent variable is responsible for the difference between the means of two groups in an experiment, it is necessary to determine the.
A)difference expected from sampling error alone
B)effect expected from the dependent variable
C)variation due to the level of alpha
D)difference due to the independent variable

Accepted Answer

To conclude that the independent variable is responsible for the difference between the means of two groups in an experiment, it's essential to determine the difference expected from sampling error alone. This helps in assessing whether the observed difference is statistically significant or could have occurred by chance.

Question 2

Sampling error implies that.
A)mistakes always will be made in selecting participants for an experiment
B)the means for samples selected from the same population will differ by some chance amount
C)the means for samples selected from the same population will always be equal
D)we can decide if an independent variable has an effect by visually inspecting the means of the different groups in an experiment

Accepted Answer

Sampling error refers to the fact that random samples from the same population will usually produce slightly different sample means. This is due to chance variability in the selection of participants for each sample. Therefore, the means for samples selected from the same population will differ by some chance amount. These differences can be statistically tested to determine if they are significant and provide evidence for a true effect of the independent variable, rather than just chance variability. Mistakes in selecting participants for an experiment may contribute to sampling error, but this is not the main definition of the term. Visually inspecting means cannot definitively determine the presence or absence of an effect in an experiment.

Question 3

Equivalent groups typically are formed by.
A)selecting two or more samples randomly from the population
B)ensuring that the proportions of males and females are the same in each group
C)matching participants for extraneous characteristics
D)randomly assigning participants to groups

Accepted Answer

Randomly assigning participants to groups helps ensure that each group is equivalent by distributing any potential confounding variables evenly across groups.

Question 4

Extraneous variables in an experiment can affect the.
A)size of the population
B)size of the needed sample
C)dependent variable
D)independent variable

Accepted Answer

Extraneous variables can affect the dependent variable, which is the main outcome being measured in the experiment. The size of the population and the needed sample are determined by the research design, while the independent variable is manipulated by the researcher and should remain constant throughout the experiment.

Question 5

The dilemma facing the experimenter is determining how large a difference between the sample means is enough to decide that something other than is at work in the experiment.
A)the independent variable
B)a treatment effect
C)sampling error
D)systematic variation

Accepted Answer

The correct answer is C) sampling error. The dilemma described is about determining when a difference between sample means is significant enough to attribute it to factors other than random variation or noise in the data, which is essentially what sampling error refers to. Sampling error occurs because a sample is only a part of the population, and there can be random differences between the sample and the population that are not due to any experimental manipulation or treatment effect.

Question 6

A simulated treatment condition in an experiment is called a(n) control.
A)simulated
B)experimenter
C)confounded
D)placebo

Accepted Answer

A simulated treatment condition in an experiment is called a placebo, not a control. A control condition is a standard condition that is used as a baseline for comparison with the experimental condition. A confounded variable is an extraneous variable that has an effect on the dependent variable, making it difficult to interpret the results. An experimenter refers to a researcher who conducts an experiment.

Question 7

An independent variable must have at least levels.
A)one or more
B)two or more
C)three or more
D)four or more

Accepted Answer

An independent variable must have at least two levels in order for it to be manipulated and compared in an experiment. Only one level would not allow for comparison, and three or more levels may be unnecessary or impractical.

Question 8

Equivalent groups are expected to.
A)be exactly the same in every way
B)not differ in any systematic way before being given the independent variable
C)represent different populations
D)have bimodal distributions

Accepted Answer

Equivalent groups are groups that do not differ in any systematic way before being given the independent variable. This ensures that any differences observed between the groups after the manipulation of the independent variable can be attributed to the variable itself and not to pre-existing differences between the groups. A and D are wrong because equivalent groups do not have to be exactly the same in every way, and they do not necessarily have bimodal distributions. C is also incorrect because equivalent groups can come from the same population.

Question 9

A placebo control group in an experiment would.
A)not be administered the dependent variable
B)receive a simulated treatment condition
C)be randomly selected but not randomly assigned
D)not be considered an equivalent group

Accepted Answer

A placebo control group is a group that receives a simulated treatment condition, which is intended to be identical to the treatment given to the experimental group but does not contain the active ingredient. This control group allows researchers to determine the efficacy of a treatment by comparing the outcomes of the experimental group to those of the placebo group, which is influenced by the placebo effect. Therefore, option B is the correct answer. Options A, C, and D are incorrect because they do not accurately reflect the purpose or characteristics of a placebo control group.

Question 10

If two groups are expected to differ only by chance before the independent variable is given, then the groups are considered to be.
A)separate but equal
B)identical
C)equivalent
D)matched

Accepted Answer

If the groups are expected to differ only by chance, then they are not matched and are not necessarily identical. Therefore, the best choice is C, which indicates that the groups are equivalent in terms of relevant characteristics.

Question 11

When two or more groups are used in an experiment, the number of subjects in each group is indicated by.
A)N
B)#S
C)nA
D)NS

Accepted Answer

The number of subjects in each group is typically indicated by a lowercase letter following the group's label, such as n for group A and n for group B. Therefore, option C (nA) is the best choice.

Question 12

When two or more groups are used in an experiment, the total number of subjects in the experiment is indicated by.
A)N
B)#S
C)nA
D)NS

Accepted Answer

The total number of subjects in an experiment, regardless of how many groups or conditions are being tested, is typically denoted by the letter N.

Question 13

In actual experimentation, random sampling rarely is used. Rather, sampling typically is used.
A)stratified
B)clustered
C)occasional
D)convenience

Accepted Answer

Convenience sampling is often used in actual experimentation due to its ease and practicality, despite the potential for bias and less representativeness compared to random sampling.

Question 14

Obtaining participants for an experiment by asking people accessible to the experimenter to participate is called sampling
A)simple random
B)valid
C)convenience
D)experimental

Accepted Answer

Convenience sampling involves obtaining participants who are readily available and accessible to the experimenter, which is the method described in the question. However, simple random sampling would be a more preferred method as it ensures that every individual in the population has an equal chance of being selected for the experiment. Valid sampling refers to the sampling technique that accurately represents the population being studied, while experimental sampling is not a valid option as it is not a recognized sampling technique.

Question 15

Which of the following occurs first when performing an experiment?
A)Predicting a relationship between an independent variable and a dependent variable.
B)Selecting the level of alpha.
C)Identifying extraneous variables.
D)Forming equivalent groups.

Accepted Answer

Predicting a relationship between an independent variable and a dependent variable typically occurs first in the experimental process, as it involves formulating a hypothesis that guides the direction of the experiment.

Question 16

Random assignment of participants requires that.
A)every person selected for the experiment has an equal chance of being assigned to any one of the treatment groups
B)the selection of one person to participate in the experiment is independent of the selection of any other person
C)all members of a population have an equal chance of being selected to participate in the experiment
D)all the above

Accepted Answer

Random assignment specifically refers to the process of assigning participants to different groups in an experiment, ensuring each participant has an equal chance of being placed in any group.

Question 17

Variables other than the independent variable that can affect the dependent variable are called variables.
A)distracter
B)interrupter
C)intervening
D)extraneous

Accepted Answer

Variables other than the independent variable that can affect the dependent variable are called extraneous variables.

Question 18

An experiment in which one independent variable is manipulated and two equivalent groups of subjects are formed is using a design.
A)one-factor within-subjects
B)one-factor between-subjects
C)two-factor within-subjects
D)two-factor between-subjects

Accepted Answer

In a one-factor between-subjects design, one independent variable is manipulated and two equivalent groups of subjects are formed. This is because the subjects are randomly assigned to one of the two groups, rather than participating in both conditions like in a one-factor within-subjects design. Therefore, option B is the best choice for this experiment.

Question 19

In an experiment designed to measure the effect of a drug on behavior, one group may be given a medication with no active ingredient; this group is identified as a(n) control group.
A)dependent variable
B)confounded
C)experimental treatment
D)placebo

Accepted Answer

The term "placebo" refers to a medication with no active ingredient, which is often given to the control group in a study to determine the true effects of the experimental treatment. The other answer choices do not accurately describe the role of the control group in this scenario.

Question 20

An experimenter manipulates the independent variable of the difficulty of a list of words a person is asked to memorize. One group of participants is given an easy list to memorize, the second group of participants is given a difficult list of words to memorize. The levels of this independent variable are.
A)list difficulty
B)the number of participants in each group
C)easy list and difficult list
D)the number of words memorized

Accepted Answer

The levels of the independent variable (list difficulty) are the specific conditions or values that the independent variable can take, which in this case are the "easy list" and "difficult list."

Quiz 9: The Basics of Experimentation and Testing for a Difference Between Means

To decide that the independent variable is responsible for the difference between the means of two groups in an experiment, it is necessary to determine the.

Sampling error implies that.

Equivalent groups typically are formed by.

Extraneous variables in an experiment can affect the.

The dilemma facing the experimenter is determining how large a difference between the sample means is enough to decide that something other than is at work in the experiment.

A simulated treatment condition in an experiment is called a(n) control.

An independent variable must have at least levels.

Equivalent groups are expected to.

A placebo control group in an experiment would.

If two groups are expected to differ only by chance before the independent variable is given, then the groups are considered to be.

When two or more groups are used in an experiment, the number of subjects in each group is indicated by.

When two or more groups are used in an experiment, the total number of subjects in the experiment is indicated by.

In actual experimentation, random sampling rarely is used. Rather, sampling typically is used.

Obtaining participants for an experiment by asking people accessible to the experimenter to participate is called sampling

Which of the following occurs first when performing an experiment?

Random assignment of participants requires that.

Variables other than the independent variable that can affect the dependent variable are called variables.

An experiment in which one independent variable is manipulated and two equivalent groups of subjects are formed is using a design.

In an experiment designed to measure the effect of a drug on behavior, one group may be given a medication with no active ingredient; this group is identified as a(n) control group.