Measurement and Methodology Flashcards
This section comprises 11-13% of the Psychology GRE subject test. When finished with this deck, you should have a better understanding of the following: Test Construction, Reliability, Validity, Research Designs, Statistical Procedures, Scientific Method, Analysis and Interpretation of Findings.
Define:
scientific method
general procedures psychologists use for gathering and interpreting data
Define theory as it relates to research methods.
organized, testable explanation of phenomena
Other researchers must be able to replicate the results of an experiment to validate its conclusions.
What is replication?
obtaining similar results to a previous study using the same methods
What is hindsight bias?
explaining why something happened after it has occured
What is a controlled experiment?
researchers systematically manipulate a variable and observe the response in a laboratory
Define:
hypothesis
prediction of how two or more factors are related
How do researchers specifically define what variables mean?
Researchers use operational definitions to precisely describe variables in relation to their study. For example, “effectiveness of studying” can be operationally defined with a test score.
What is the difference between an independent variable and a dependent variable in an experiment?
The factor being manipulated is the independent variable. The factor being measured is the dependent variable.
Identify the independent and dependent variables:
If we test the hypothesis that students who Brainscape to study, rather than simple flash cards, will learn more (as measured by higher test scores), then what is the independent variable? What is the dependent variable?
- independent: method of studying (Brainscape versus regular flashcards)
- dependent: amount learned, as measured by their test scores
Define population as it relates to research methods.
all the individuals to which the study applies
Define sample as it relates to research methods.
subgroup of a population that constitutes participants of a study
What type of sample should be used in research?
Larger sample sizes are ideal because they are the most representative of the population.
The amount of difference between the sample and population is called __________.
sampling error
Define random selection as it relates to research methods.
every individual from a population has an equal chance of being chosen for the sample
Which individuals are in the experimental group?
subjects who receive the treatment or manipulation of the independent variable
Which individuals are in the control group?
subjects who do not receive any treatment or manipulation
Subjects who receive the treatment are part of the __________, while those who do not receive the treatment belong to the __________.
experimental group; control group
What type of experimental design uses experimental and control groups?
A between-subjects design uses an experimental group and a control group to compare the effect of the independent variable.
Which process is used to try to ensure there are no preexisting differences between the control group and the experimental group?
Random assignment is used to assign the sample participants into groups (e.g., experimental drug or placebo).
Random assignment means neither the experimentor nor the participants decide in which group the participants will be, and each participant has an equal chance of being assigned to a given study groups (e.g., treatment vs. placebo).
Define:
confounding variable
- any difference between the experimental group and the control group, besides the effect of the independent variable
- a.k.a. third variable
- makes the phenomenon at hand even more difficult to study because of complex interaction effects
List four types of confounding variables.
- experimenter bias
- demand characteristics
- placebo effect
- lack of counterbalancing
Define experimenter bias as it relates to confounding variables.
Experimenter bias occurs when a researcher’s expectations or preferences about the results of the study influence the experiment.
Define demand characteristics as they relate to confounding variables.
clues the participants discover about the intention of the study that alter their responses
Define placebo effect as it relates to confounding variables.
responding to an inactive drug with a change in behavior because the subject believes it contains the active ingredient
What is the Hawthorne effect?
individuals who are being experimented on behave differently than in their everyday life
What type of experimental design uses each participant as his/her own control?
A within-subjects design exposes each participant to the treatment and compares their pre-test and post-test results. This design can also compare the results of two different treatments administered.
What is a single-blind procedure?
research design in which the subjects are unaware if they are in the control or experimental group
What is a double-blind procedure?
research design in which neither the experimenter nor the subjects are aware who is in the control or experimental group
Single-blind procedures aim to eliminate the effects of __________, while double-blind procedures use a third party researcher to omit the effects of __________.
demand characteristics; experimenter bias
How are quasi-experiments different from controlled experiments?
Random assignment is not possible in quasi-experiments.
What types of research are considered quasi-experiments?
Differences in behavior between:
- males and females
- various age groups
- students in different classes
Define:
correlational research
- establishes a relationship between two variables
- does not determine cause and effect
- used to make predictions and generate future research
List three methods of data collection
- naturalistic observation
- surveys
- tests
Which two conditions must be met for an experiment to be considered a true experiment?
- the researcher manipulates the independent variable
- all participants are randomly assigned to the experimental and control condition
So, for instance, a study that compares how men versus women do on a given task would not be a true experiment because it is not possible to assign people to group (gender). (This example would be a quasiexperiment.)
Define naturalistic observation as it relates to correlational research.
Naturalistic observation consists of field observation of naturally occuring behavior, such as the way students behave in the classroom. There is no manipulation of variables.
What are surveys and why are they not always accurate?
- type of correlational research
- questionnaires and interviews given to a large group of people about their thoughts or behavior
- individuals aim to be politically correct and socially accepted, leading them to give false answers
Define tests as they relate to correlational research.
research method that measures individual traits at a specific time and place
__________ studies start by looking at an effect and then attempt to determine the cause.
Ex post facto
What is the difference between the reliability and validity of a test?
- Reliable – consistent. When administered properly, does a test give similar results when used on different occasions?
- Valid – useful, meaningful. Does it measure what it claims to measure?
In order to be valid, a measure must be reliable. However, a measure can be reliable without being valid. For instance, imagine a scale that always reads 212 pounds, no matter what the weight is of the person who stands on it. That scale would be a reliable measure, but not a valid measure.
What is a case study?
- detailed examination of one person or a small group
- beneficial for understanding rare and complex phenomena in clinical research
- not always representative of the larger population
What are the strengths and weaknesses of this research method?
experiments
Strengths:
- determine cause and effect relationship between variables
- control over confounding variables
Weaknesses:
- no real-world generalizability
- expensive
- time-consuming
What are the strengths and weaknesses of this research method?
correlational research
Strengths:
- easy to administer surveys or tests
- inexpensive
- minimal time needed
- substantial real-world generalizability
Weaknesses:
- no control over confounding variables
- skewed or biased results
- establishes a relationship, not causation
Define:
statistics
analysis of numerical data regarding representative samples
1) __________ data include measurements, such as scores on the Wisconsin Card Sorting Task (behavioral example) or scores on the Magical Ideation Scale (self report example), that can be readily expressed using numbers.
2) __________ data, such as clinical interviews, can be very descriptive and rich, but are challenging and ambiguous to interpret.
- Quantitative
- Qualitative
What are the four scales of measurement?
- nominal
- ordinal
- interval
- ratio
Define:
nominal scale
Data that are categorical: Numbers have no meaning except for convenience as labels.
Examples:
Hair Color (possibly coded red = 1; grey = 2; black = 3; brown = 4; blond = 5…)
Political Party (possibly coded Democrat = 1; Republican = 2; Independent/Other =3)
Gender (Male = 1; Female = 2; Prefer not to reply = 3).
Define:
ordinal scale
numbers are used as ranks
Examples:
The runner who wins the race is scored as 1, the runner who comes in second is scored as 2, the third is scored as 3, and so on.
Define:
interval scale
numbers that have a meaningful difference between them
Example:
Temperature: The difference between 10°F and 20°F is the same as between 30°F and 40°F.
Define:
ratio scale
numbers that have a meaningful ratio between them on a scale with a real zero point
Example:
Weight and height: If you weight zero pounds, you have no weight. 100 pounds is twice as heavy as 50 pounds.
Would temperature of Celcius and Farenheit be measured on an interval scale or a ratio scale?
interval
If the temperature is 0°F, there is not “no temperature.” There is not a meaningful ratio between values. 100°F is not twice as hot as 50°F.
What are descriptive statistics?
numbers that summarize a set of research data from a sample
Define:
frequency distribution
an orderly arrangement of scores indicating the frequency of each score
What is the difference between a histogram and a frequency polygon?
A histogram is a bar graph and a frequency polygon is a line graph or a bell curve.
Define and list the three types of:
central tendency
Measures of central tendency describe the most typical scores for a set of research data.
- mode
- median
- mean
Define in terms of central tendency:
mode
most frequently occurring score in the data set
Define in terms of central tendency:
median
the middle score when the data is ordered by size
Define in terms of central tendency:
mean
arithmetic average of the scores in the data set
If two scores appear most frequently, the distribution is __________, and if there are three or more appearing most frequently, it is __________.
bimodal; multimodal
Which measure of central tendency is the most representative? The least representative?
- mean is usually most representative, unless there are extreme outliers that pull the mean in a particular direction
- median is less sensitive to outliers, but is a weak statistic
- mode is the least representative
Define:
normal distribution
a bell-shaped, symmetrical curve that represents data about many characteristics, including the distribution of many human characteristics
![](https://s3.amazonaws.com/brainscape-prod/system/cm/001/271/637/a_image_thumb.gif?1659395493)
In a normal distribution, approximately two thirds of the population will be within plus or minus one standard deviation of the norm (mean). Approximately 95% of the population will be within plus or minus two standard deviations of the mean. Over 99% of the population will fall within plus or minus three standard deviations of the mean.