Test 3 Flashcards
In a __________, the subjects in each group are different; that is, different people serve in control and experimental groups. (Different subjects are assigned to each group.)
between-subjects design
By _______ _______ participants to conditions, we are trying to make the two groups as equivalent as possible.
randomly assigning
A study is researching the effects of a study strategy on memory. One group uses the device while studying and another group does not use the device while studying. Each person in both groups is then given a memory test to determine any differences. Assuming everything was held constant (controlled), any difference observed would have to be due to the independent variable. If the study strategy group performed better, we could conclude that the study strategy caused memory to improve.
This memory study is known as a ___________.
posttest-only control group design
An experimental design in which the dependent variable is measured after the manipulation of the independent variable.
posttest-only control group design
An experimental design in which the dependent variable is measured both before and after manipulation of the independent variable.
pretest/posttest control group design
The ___________ has the added advantage of ensuring that the subjects are equivalent at the beginning of the study.
pretest/posttest control group design
The pretest/posttest control group design is not considered necessary if :
the subjects are randomly assigned and if the researcher uses a sufficiently large sample of subjects.
There are disadvantages of pretest/posttest control group design, including the possibility of:
increasing demand characteristics and experimenter effects. (subject could guess what researchers are studying before posttest, and there is more opportunity for an experimenter to influence the subjects)
A design with four groups that is a combination of the posttest only control group design and the pretest/posttest control group design, which minimizes the disadvantages and maximized the advantages.
Solomon four-group design.
A ______ is an uncontrolled extraneous variable or flaw in an experiment.
confound
If a study is confounded, then it is impossible to say:
whether changes in the dependent variable were caused by the independent variable or by the uncontrolled extraneous variable.
Maximizing control of _________ can be very difficult.
human subjects
The extent to which the results of an experiment can be attributed to the manipulation of the independent variable rather than to some confounding variable.
internal validity
The process of determining whether a hypothesis is supported by the results of the research project is referred to as ______.
hypothesis testing
It is impossible, statistically to demonstrate that something is true.
True or False
True
Why do researchers create a null hypothesis?
Because statistical techniques are better at determining that something is not true, the researcher creates a null hypothesis to disprove, thus proving their initial hypothesis to be true.
The hypothesis predicting that no difference exists between groups being compared is called the _____________.
null hypothesis
Ho (capital H, little zero)
null hypothesis
Whatever the research topic, the ___ predicts the opposite of that.
null hypothesis
Create a null hypothesis (worded and in statistical notation) for the following statement:
Children who attend academic after-school programs have different IQ scores than those who do not.
Ho = Children who attend academic after-school programs have the same intelligence level as children that do not.
Ho: µo = µ1
or
Ho : µacademic program = µgeneral pop.
Statistics allow us to _______ a hypothesis.
disprove or falsify
If the null hypothesis is not supported, then the original hypothesis is ______.
supported or true
The hypothesis that the researcher wants to support, predicting that a significant difference exists between groups being compared is called the ______.
alternative hypothesis (Ha) or the research hypothesis (H1)
Create the statistical notation for the following research hypothesis:
Children who attend academic after-school programs have different IQ scores than those who do not.
Ha: µ1 ≠ µ2;
or
Ha: µacademic program ≠ µgeneral pop.
An alternative hypothesis in which the researcher predicts that the groups being compared differ but does not predict the direction of the difference.
two-tailed hypothesis
Ha: µ1 ≠ µ2
is a ________ hypothesis.
two-tailed (or non-directional) hypothesis, because it does not predict the direction of the difference. For example, it does not say Ha: µ1 > µ2
When using a two-tailed hypothesis, the researcher expects to find differences between the groups but is unsure what the differences will be.
True or False
True
An alternative hypothesis in which the researcher predicts the direction of the expected difference between the groups is known as a __________.
one-tailed hypothesis
Ha : µo > µ1 is a _________ hypothesis
one-tailed hypothesis, because it is directional
Write the null hypothesis for the following:
Ha : µo > µ1
Ho : µo ≤ µ1
What are two types of hypothesis that can describe the following?
Ho : µo ≤ µ1
null hypothesis (Ho), and one-tailed (directional, ≤)
Ho: µ academic program ≤ µ general pop.
If the data collected found that the mean intelligence level of the children in academic after-school programs is “significantly” higher than the mean intelligence level for the population, then we would ________ the null hypothesis and ________ the alternative hypothesis.
reject the null, support the alternative