Question

QUESTION 2

1. Which causal criterion is established in an experiment by tests of statistical significance?

	a.	association
	b.	direction of influence
	c.	nonspuriousness (elimination of rival explanations)

7.7 points   

QUESTION 3

1. What is the purpose of tests of statistical significance in an experiment?

	a.	to establish direction of influence
	b.	to determine if random assignment created similar experimental and control groups
	c.	to determine the generalizability of the findings
	d.	to determine if chance is a reasonable explanation of experimental results

7.7 points   

QUESTION 4

1. In a laboratory experiment on helping behavior, two variables are manipulated: (1) others’ presence (whether participants worked alone on a task or with others) and (2) type of task (whether participants were timed or untimed on the task). The dependent measure is the number of seconds between someone’s request for help and the participant’s response. What type of experimental design is this?

	a.	posttest-only control group design
	b.	pretest-posttest control group design
	c.	2 × 2 factorial design
	d.	2 × 4 factorial design

7.7 points   

QUESTION 5

1. In comparison with laboratory experiments, field experiments

	a.	rarely involve manipulation of the independent variable.
	b.	afford less control over design and measurement.
	c.	are less likely to raise ethical issues.
	d.	usually involve more extensive debriefing

Answer 1

Answer 2; (a)

The first criterion for establishing a causal effect is an empirical (or observed) association (sometimes called a correlation) between the independent and dependent variables.

Answer 3: (b)

A statistical test provides a mechanism for making quantitative decisions about a process or processes. The intent is to determine whether there is enough evidence to "reject" a conjecture or hypothesis about the process. The conjecture is called the null hypothesis.

Answer:4 (b)

ANSWER 5 (B)

AS Field experiments, like lab experiments, randomly assign subjects (or other sampling units) to either treatment or control groups in order to test claims of causal relationships. Random assignment helps establish the comparability of the treatment and control group, so that any differences between them that emerge after the treatment has been administered plausibly reflect the influence of the treatment rather than pre-existing differences between the groups. The distinguishing characteristics of field experiments are that they are conducted real-world settings and often unobtrusively.