Unit 0 - Research Methods and Data Interpretation

Random sample (representative)

sample that fairly represents a population because each member has an equal chance of inclusion

Hindsight Bias (I-Knew-It-All-Along Bias)

tendency to believe after learning an outcome that one would have foreseen it

Overconfidence

being more confident than correct;

people think that hindsight is so obvious

Perceiving order in random events

Finding patterns in disconnected events

Critical thinking

Thinking that does not blindly accept arguments and conclusions.

3 elements of the scientific attitude

curiosity, skepticism, humility

Theory

explanation using organized information and observations to predict behaviors and events

(Supported by evidence)

Hypothesis

testable prediction

(Constructed before any research is done)

Operational definition

statement of procedures that identifies how variables will be measured; makes replication possible

Replication

the process of repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances

Population

all cases in the group being studied from which samples may be drawn

Sample

a subset of the population

Case Study

in-depth investigation;

collect lengthy, detailed information about a person's background

Survey

use questionnaires to gather information on feelings, opinions, and behavior patterns

Naturalistic Observation

studying subjects without intervening directly

Longitudinal Study

study same group of people over an extended time period

Cross-Sectional Study

studies different age groups at the same time (developmental life span changes)

Structured interviews

interviews in which all applicants are asked the same set of standardized questions

Correlation

A measure of the relationship between two variables (how well either factor predicts the other)

Scatterplot

graphed cluster of dots

Positive (direct)

two sets of scores rise or fall together

Negative (inverse)

two sets of scores relate inversely, one set goes up, other goes down

Illusory correlations

perceived but nonexistent correlation;

we notice and recall instances that confirm our belief that a correlation exists

Random assignment

assigns participants to experimental and control groups by chance;

minimizes preexisting differences between those assigned to different groups

Independent variable

manipulated variable

Dependent variable

measured outcome

Confounding variables (extraneous)

factor other than the independent variable that might affect the experiment

Experimental group

group exposed to one version of the independent variable

Control group

group not exposed to the treatment;

comparison to experiment

Experimental Bias

a mistake in the design of an experiment that makes a particular result more likely

Single Blind Study

participants are uninformed about what treatment, if any, they are receiving

Double Blind Study

both participants and experimenters are blind about whether the participants have received the treatment or a placebo

Central Tendency

helps to know something about the amount of variation in the data

Mean

arithmetic average;

sensitive to extreme scores

Median

midpoint, 50th percentile;

middle number in the data

Mode

most frequently occurring scores in distribution;

can have multiple modes or no modes

Positively skewed distribution

distribution is lopsided positively;

lots of low numbers

Negatively skewed distribution

distribution is lopsided negatively;

lots of high numbers

Range

difference between highest and lowest scores in distribution

Standard deviation

average distance of scores around mean;

square root of variance

Reliability

test that yields consistent results from one time and place to another (test - retest)

Validity

test that measures what it is set out to measure

Inferential statistics

numerical data that allow one to generalize (infer) from sample data the probability of something being true of a population

Statistical Significance

statistical statement of how likely it is that an obtained result occurred by chance

Meta-analysis

a "study of studies" that combines the findings of multiple studies to arrive at a conclusion

Effect size

what you expect results to be with the data or product

Descriptive statistics

organize, summarize, describe data, frequently use graphs or charts

Informed consent

ethical principle that research participants be told enough to enable them to choose whether they wish to participate

Do no harm

Protect

Confidentiality & Anonymity

treat information about individual participants confidentially

Use of deception and debriefing

postexperimental explanation of a study, including its purpose and any deceptions, to its participants

Peer review

evaluation of scientific, academic, or professional work by others working in the same field.

Falsifiable

capable of being disproved

Self report bias

the tendency of individuals to provide inaccurate or biased information about themselves

Representative sample

a sample that accurately reflects the characteristics of the population as a whole

Subject bias

a subject's behavior changes due to believed expectations of experiment

Demand characteristics

cues in an experiment that tell the participant what behavior is expected (winking, small talk, etc)

Placebo effect

improvement resulting from the mere expectation of improvement (fake pill)

Qualitative research

research that relies on what is seen in field or naturalistic settings more than on statistical data

Quantitative research

research that collects and reports data primarily in numerical form

Variables

Any measurable conditions, events, characteristics, or behaviors that are controlled or observed in a study.

Regression towards the mean

the tendency for extreme or unusual scores to fall back (regress) toward their average.

Sampling bias

a flawed sampling process that produces an unrepresentative sample

Wording effects

when a specific word used in a question affects how respondents answer the question or the order of the questions

Treatment of animals

Researchers must ensure the "comfort, health, and humane treatment" of animals and minimize "infection, illness, and pain."

IRB approval

The determination of the IRB that the clinical investigation has been reviewed and may be conducted at an institution within the constraints set forth by the IRB and by other institutional and federal Requirements. (21 CFR, sec. 56.102)

Percentile rank

the percentage of scores below a specific score in a distribution of scores

Correlational method

two different variables are observed to determine whether there is a relationship between them

Non-experimental method

relationships are studied by making observations or measures of the variables of interest

Experimental method

A method of investigation used to demonstrate cause-and-effect relationships by purposely manipulating one factor thought to produce change in another factor.

Third variable problem

the concept that a correlation between two variables may stem from both being influenced by some third variable

Bimodal

distributions with two modes (2 peaks)