Question 1

What are the two primary advantages of correlated-groups designs?

Accepted Answer

Correlated-groups designs primarily address control issues by using the same participants or matched groups, which reduces variability and increases statistical power.

Question 2

Which of the following represents the general formula for statistical tests?

Accepted Answer

The general formula for statistical tests often involves comparing the variability between groups to the error variability, which is represented by between-groups variability divided by error variability.

Question 3

Independent variables can

Accepted Answer

Independent variables can be manipulated to contrast different levels or presence/absence of a variable, and in ex post facto designs, they are measured rather than manipulated.

Question 4

Why does using a correlated-groups design reduce error variability?

Accepted Answer

In a correlated-groups design, the same participants are used in all conditions, which reduces error variability due to individual differences, as each participant serves as their own control.

Question 5

Which of the following is an advantage of independent-groups designs?

Accepted Answer

Independent-groups designs are generally easier to plan and execute because they do not require matching or pairing participants, which can be complex and time-consuming in correlated-groups designs.

Question 6

Variability in DV scores that is due to the effects of the IV is known as __________ variability.

Accepted Answer

Between-groups variability refers to the differences in DV scores that can be attributed to the effects of the independent variable (IV) across different groups or conditions in an experiment.

Question 7

In an experiment that involves two groups, there is/are _____ source(s) of variability.

Accepted Answer

There are two sources of variability: within-group variability and between-group variability.

Question 8

In a correlated-groups design, error variability due to individual differences _________, which makes it ________ to find a significant effect.

Accepted Answer

In a correlated-groups design, individual differences are controlled or reduced, which decreases error variability, making it easier to detect a significant effect.

Question 9

An experiment in which the experimenter directly manipulates the IV is known as a(n)

Accepted Answer

A true experiment involves the direct manipulation of the independent variable (IV) by the experimenter to observe its effect on the dependent variable.

Question 10

When the number of observations in each group is equal, the critical t value in a correlated groups design is ________ the critical t value in an independent-groups design.

Accepted Answer

The answer of When the number of observations in each...

Question 11

A research approach in which the experimenter cannot directly manipulate the IV but can only measure an IV because it is predetermined is known as a(n)

Accepted Answer

In an ex post facto research design, the independent variable is not manipulated by the researcher but is instead a pre-existing condition or characteristic, and the researcher observes its effects on the dependent variable.

Question 12

In a _______ design, we generally have greater certainty regarding the equality of the groups before the experiment begins than with a _______ design.

Accepted Answer

In a correlated-groups design, participants are matched or the same participants are used in all conditions, which ensures greater equality of groups before the experiment compared to a between-subjects design where different participants are used in each group.

Question 13

Suppose you conducted an experiment with 20 participants in each group. You would have _____ degrees of freedom in an independent-groups design and _____ degrees of freedom in a correlated-groups design.

Accepted Answer

In an independent-groups design, degrees of freedom are calculated as (n1 + n2 - 2), which is (20 + 20 - 2) = 38. In a correlated-groups design, degrees of freedom are calculated as (n - 1), which is (20 - 1) = 19.

Question 14

Which of the following is a similarity between the two independent-groups design and the two correlated-groups design?

Accepted Answer

Both the independent-groups design and the correlated-groups design involve one independent variable with two groups, but they differ in how participants are assigned to these groups.

Question 15

The goal in an experiment is to __________ the between-groups variability and ___________ the error variability.

Accepted Answer

The goal in an experiment is to maximize the between-groups variability to detect differences due to the treatment and minimize the error variability to reduce noise and increase the reliability of the results.

Question 16

A correlated-groups design reduces error variability by reducing error due to

Accepted Answer

A correlated-groups design, such as a repeated measures or matched groups design, primarily reduces error variability by controlling for individual differences, as the same participants or matched participants are used across conditions.

Question 17

________ statistical values are associated with significant differences in your experiment.

Accepted Answer

Large statistical values typically indicate significant differences in experiments, as they suggest a strong effect or relationship that is unlikely to be due to chance.

Question 18

Variability in DV scores that is due to factors other than the IV is known as _________ variability.

Accepted Answer

Error variability refers to the variability in dependent variable scores that cannot be attributed to the independent variable, often due to random or uncontrolled factors.

Question 19

Degrees of freedom in the two-correlated groups design are _______, and degrees of freedom in the two-independent groups design are _________.

Accepted Answer

In the two-correlated groups design, the degrees of freedom are N - 1 for the numerator and N - 1 for the denominator. In the two-independent groups design, the degrees of freedom are N - 2 for the numerator and N - 2 for the denominator.

Question 20

Error variability consists of

Accepted Answer

Error variability includes individual differences, measurement errors, and extraneous variation, as all these factors contribute to the variability in data that is not explained by the variables being studied.

Quiz 10: Designing, Conducting, Analyzing, and Interpreting Experiments With Two Groups