ch 8 Flashcards
When the effects of the independent variable and an uncontrolled variable are intertwined so that one cannot determine which of the variables is responsible for the observed effect on the dependent variable in an experiment _____ occurs .
confounding
A posttest-only design has a high degree of internal validity because __
the groups are equivalent prior to the introduction of an independent variable
As a final step of a posttest-only design, the effect of the ______ is measured.
independent variable
A research group plans to analyze the effect of college education on the social behavior of Americans. To increase the likelihood that any difference between the control group and the experimental group is due to the effect of the independent variable, the research group should ____
increase sample size
The dropout factor in experiments is called _____or mortality
attribution
disadvantages of pretest:
It can enable participants to figure out what the study is about.
It can be time-consuming.
In the context of the pretest-posttest design, the likelihood that the groups will differ in any systematic way decreases as the
sample size increases
Although randomization is likely to produce equivalent groups, it is possible that, with small sample sizes, the groups will not be equal. In such cases, how do researchers ensure that the groups are equivalent?
They use a pretest to tell whether the groups are equivalent to begin with.
A study using the pretest-posttest design was conducted to determine the effect of regular strenuous physical exercise on students’ grades. The researchers randomly divided the participants into an experimental and a control group. The study was designed for a period of 12 months with 100 students in each group. After 6 months, only 40 participants remained in the experimental group. The results obtained at the end of the study were faulty. In this scenario, the faulty results can most likely be attributed to Blank
high attrition rates
The experimental design in which half the participants receive only the posttest, and the other half receive both the pretest and the posttest is formally called a
Solomon four-group design
A procedure in which participants are randomly assigned to various conditions so that each participates in only one group is called a(n)___
independent group design
An independent groups design is commonly known as a between-subjects design because comparisons are made between
different groups of participants
A repeated measures design is also called a(n)
within-subjects design
A researcher plans to assess the effect of physical exercise on performance in an exam by conducting two tests; one test is to be conducted with participants performing physical exercise before writing an exam and the other with participants writing the exam without performing any prior physical exercise. In the context of repeated measures design, what is the approach that the researcher should adopt to assess this effect?
The researcher should conduct the tests under both conditions on the same group of participants.
The repeated measures design is called so because
each participant is measured after receiving each level of the independent variable
