Research Design

Question 1

Variables

Answer 1

• Independent
• Dependent
• Confounding
• Quasi-Independent

Question 2

Independent Variable

Answer 2

o Manipulated by the researcher (it’s the presumed agent of change)

Question 3

Dependent Variable

Answer 3

o Measured by the researcher (determines if IV has an effect)

Question 4

Confounding Variable

Answer 4

o Reduces internal validity (this variable is an extraneous variable. It varies systematically with the IV)

Question 5

Quai-Independent Variable

Answer 5

o An experiment that uses existing groups (rather than random assignment) to determine condition

Question 6

Types of Designs

Answer 6

Correlational
Descriptive
Experimental

Question 7

Correlational Design

Answer 7

How are these variables related?
a type of research design where a researcher seeks to understand what kind of relationships naturally occurring variables have with one another. In simple terms, correlational research seeks to figure out if two or more variables are related and, if so, in what way

Question 8

Descriptive Design

Answer 8

a scientific method which involves observing and describing the behavior of a subject without influencing it in any way.

Question 9

Experimental Design

Answer 9

What is the effect of the IV on the phenomenon?

how participants are allocated to the different conditions (or IV levels) in an experiment

Question 10

ANOVAs

Answer 10

Analysis of variance is a statistical test to determine if all sample groups in a study are affected by the same factors, and if they are affected to the same degree. The groups are kept separate and tests are done independently on each group, but the results are then compared. The sample groups are examined to see if the average within each group is the same and how much impact different variables have on the test.

Question 11

Type I Error

Answer 11

False positive – reject null hypothesis but it is true

Question 12

Type II Error

Answer 12

(miss) do not reject null when there is a real effect

Question 13

Measures of central tendency

Answer 13

• (mean, median, and mode) are statistics that describe the center of a data set. The mean tells us the average value or score; the median tells us the midpoint in the range of values; and the mode tells us the most common value in the data set.

Question 14

Effect Size

Answer 14

• the size of a relationship between two variables.
• Sometimes effect size is known as treatment effect because it is often used when dealing with therapeutic interventions (ie., this treatment is shown to be more effective than another at treating a specific disorder).

Question 15

Reliability

Answer 15

• the extent to which a test or other instrument is consistent in its measures.
• For example, a weight scale can be judged reliable if measures for a 25-pound weight do not vary over time or change for subsequent weightings.
• Reliability is an important concept in science. If a test is not reliable, we cannot find the answers to our questions.

Question 16

Validity

Answer 16

• If the test does indeed measure what it is intended to measure, then we can say that the test is valid (or has validity).
• tests are usually judged according to their validity and their reliability (if the test produces similar results each time the test is taken).
• Tests that are valid are also reliable
• a test might be reliable without it being valid.

Question 17

Double-blind Study

Answer 17

• is one in which neither the participants nor the experimenters know who is receiving a particular treatment.
• This procedure is utilized to prevent bias in research results. Double-blind studies are particularly useful for preventing bias due to demand characteristics or the placebo effect.

Question 18

Distribution Curve

Answer 18

• shows how often an experiment will produce a particular result
• The curve is symmetricaland bell shaped, showing that trials will usually give a result near the average, but will occasionally deviate by large amount
• The width of the “bell” indicates how much confidence one can have in the result of an experiment — the narrower the bell, the higher the confidence.

Question 19

Standard Error of Estimate

Answer 19

• the measure of variation of an observation made around the computed regression line. Simply, it is used to check the accuracy of predictions made with the regression line.

Question 20

Standard Error of Measurement

Answer 20

• estimates how repeated measures of a person on the same instrument tend to be distributed around his or her “true” score. The true score is always an unknown because no measure can be constructed that provides a perfect reflection of the true score

Question 21

Percentile Ranks

Answer 21

• The percentile rank of a score is the percentage of scores in its frequency distribution that are equal to or lower than it. For example, a test score that is greater than 75% of the scores of people taking the test is said to be at the 75th percentile, where 75 is the percentile rank.