PSYC 270 Exam 2, Part 2

3 necessary conditions for causation

Why conduct a non-experimental study?

It is not possible to make determinations of causation with a correlational study because of _______ and ______

This is the correlation between X and Y, with Z held constant

a variable that accounts for the relationship between 2 other variables

variable that specifies when effects will hold

Comparisons of two or more groups that are differentiated on a preexisting variable/grouping; the variable is measured, not manipulated

examples of quasi-experimental research

Measuring attributes over time can also be ________ IF there is not a random assignment to conditions OR a control group for comparison

Quasi-Experimental research may be subject to

weakness of non-experimental study

Pros of correlational research

Magnitude and Sign of r

simultaneously analyzing multiple variables

in regression analysis, the _____ is the known variable; The ______ is the predicted variable

Regression analysis can be extended to ________ (using several predictors for one criterion)

Quasi-experiments may look a lot like an experiment, but it lacks ___________

In quasi-experiments we use a non-manipulated independent variable, or...

a research design where patterns of scores over time are compared before a treatment is implemented and after a treatment is implemented

If I measure your attitudes about research methods before we begin the class, and then again after class,
then the change in attitude (better or worse) could be because of the class or some other events that occurred during the between the tests

during time series design, treatment is an independent event that researchers have no control over

during time series design, treatment is implemented by the
researcher (i.e., examining a new therapy technique).

advantages to single-subject designs:

major disadvantages to single-subject designs

commonly used single-subject designs

a statistical technique that allows you to combine effect sizes or significance testings from many different studies

Committee that reviews proposals of intended research and evaluates if the research is ethical and if the rights of the participants are being protected

written or verbal acknowledgment that subjects know
what they are getting into and that they have these rights

by commission, when a research deliberately misleads the participant (provides false information, or uses a confederate)

by omission, when a researcher withholds information about the nature of a study from the participants (not fully
explaining the purpose of the study when it starts)

describing the nature of the research after participation

a strategy for selecting study participants in which each and every person has an equal and independent chance of being selected

the most straightforward of the random sampling strategies. We use this strategy when we believe that the population is relatively homogeneous for the characteristic of interest

take every nth person from the sampling frame; not a random sampling strategy

treats the population as though it were two or more separate populations and then randomly samples within each

begin by stratifying the population into relevant subgroups and then random sampling within each subgroup. The number of participants that we recruit from each subgroup is equal to their proportion in the population.

useful when it would be impossible or impractical to identify every person in the sample; ex: Rather than randomly sample 10% of students from each class, which would be a difficult task, randomly sampling every student in 10% of the classes would be easier

Ex: To obtain a representative national sample, researchers may select zip codes at random from each state. Within these zip codes, streets are randomly selected. Within each street, addresses are randomly selected

uses a "man-on-the-street" technique to recruit those who wander by or selects a sampling frame that does not accurately reflect the population

targets a particular group of people

selects a particular group of people but it does not come close to sampling all of a population

A key aspect of experiments that allows test of causal relationships is the manipulation of the ________

Another key feature of experiments is the control of factors that could affect the results but are not part of the independent variable(s) manipulated. These extraneous factors are called _________

If confounding variables are not ______, the causal relationship between the independent and dependent variables will be unclear

If an EV affects the groups in an experiment differentially, we do not know whether the IV or EV is resulting in the differences in the DV. In this case, we say that the results of the experiment are:

an error in data collection based on poor measuring
instruments or human error

Extent to which items on a test, inventory, questionnaire, adequately measure the construct they are supposed to measure

degree to which a test or other measure assesses the underlying theoretical construct it is supposed to
measure

Two major types of validity

Extent to which a measure correlates with other indicators of a construct

Extent to which a measure does not correlate with other measures that do not measure the construct of interest

Are the statistical tests accurate and appropriate? The degree to which conclusions reached about relationships between variables are justified

Do the results apply to the broader population of people and situations? Generalization.

Was the independent variable the sole cause of the change in the dependent variable? Have we ruled out all possible sources of confounding?

incorrectly rejecting null hypothesis

incorrectly failing to reject the null hypothesis

The tendency by participants to act differently than normal because they know they are being studied

The tendency by participants to respond to what they think the experimenter wants (or demands) from them

The tendency to feel inadequate or to experience unease when being observed

Treatment effects that are due to participants’ expectations that the treatment will work

Any factor that creates groups that are not equal at the start of the study; threat to validity

Changes due to normal growth or predictable changes; threat to validity

Loss of participants during a study. The participants who drop out may be different from those who continue; threat to validity

Changes due to an event that occurs during the study, which might have affected the results; threat to validity

Changes in participants’ behavior in one condition because of information they obtained about the procedures in other conditions; threat to validity

Any change in the calibration of the measuring instrument (especially human measuring instruments) over the course of the study; threat to validity

Effects on performance in one condition due to experience with previous conditions; These are
of concern whenever a participant is tested more than once under different conditions; threat to validity

Changes due to the effects of previous testing; threat to validity

Participants selected because of extreme scores will on average be less extreme on a retest; very common in psyc research; threat to validity

Any preconceived idea by the researcher about how the experiment should turn out can influence the results. (not deliberate – e.g. scientific fraud)

both the participant and the experimenter are unaware of the condition the participant is assigned to

about assignment to the condition

randomly select individuals from the population for your study

One way to control extraneous factors is through ______ to the various levels of the IVs

Two or more independent variables makes it a ______

Why is random assignment used?

The most effective way to minimize many of the threats to validity is to have a _______ and ________

Way to minimize observer effect (experimenter bias):

Ways to minimize participant effects (Hawthorne, demand characteristics, evaluation app, placebo):

Way to minimize diffusion of treatment threat:

Way to minimize selection threat:

Ways to minimize history and maturation threat:

Ways to minimize testing, order effects:

Way to minimize instrumentation threat:

Ways to minimize statistical regression threat:

Ways to minimize attrition threat:

test the individual under only one treatment or research condition (sometimes referred to as independent groups)

test the same person under two or more research conditions (sometimes referred to as repeated measures)

test used when comparing 2 means

test used when comparing more than 2 means

test used when comparing more than 4 means across at least 2 factors