Basic Terms and Definitions Flashcards
Descriptive statistics
summarize, understand, and describe a group of numbers from a research study
What are examples of descriptive stats
- measure of central tendency (mean, median, mode)
2. variability (range, varience, sd)
Inferential statistics
- draw conclusions and make inferences based on numbers from a research study, but go beyond these numbers
- if there is a difference between groups
- how sure we are about our conclusions
Variable
condition or characteristic that can have different (varying) values (ex. male/female, …22,23,24…,
Score
the value of a particular person’s answer (ex. male, 25yrs old, 15 sexual partners)
Variability
how much change there is in a group of scores
Variance
a specific measure of variability
Correlational Research Designs
examines if there is a relationship between variables
- “what does knowledge of x tell us about y”
- naturally occurring variables
Experimental Research Designs
goal is to determine why something happens
- “what causes X?”
- control and manipulation of variables
Independent variable
variable that the researcher manipulates/changes
Dependent variable
variable that changes because of IV
Components of an experiment
- Must have more than one level of IV
- several, stable/reliable DVs
- control variables
- random assignment
Control variables
keeping everything else constant
Random assignment
purpose of random assignment is to create equivalent groups
Population
set of all cases of interest, generally a theoretical concept (not always measurable)
Sample
subset of population that is being studied; something to be concerned about is biased samples
Biased Samples
sample that systematically underselects or overselects from certain groups in the population
Parameter
Some characteristic of population
Statistic
some characteristic of sample
Scales of measurement
- Nominal
- Ordinal
- Interval
- Ratio
Nominal
mutually exclusive categories (yes or no)
Ordinal
placing variables in a “ranked” order (no, somewhat, yes)
Interval
equal distances between points on the scale (temp., on scale from 1-10 how helpful)
Ratio
exactly like interval scale, but has a true zero (#oof cigs smoked today)