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Terms in this set (42)
skewed distributions
asymmetrical distributions in which the majority of scores are located on one side of the distribution
normal distribution
a function that represents the distribution of variables as a symmetrical bell-shaped graph
inferential stats
indicate whether or not results are significant and apply to entire population
descriptive stats
numbers that summarize a set of data from a sample
reliability
ability of a test to yield very similar scores for the same individual over repeated testings; consistency
validity
the extent to which a test measures or predicts what it is supposed to
mean
arithmetic average
median
arrange numbers in order, middle number
mode
most frequently occurring number
range
a set of values (from highest to lowest)
percentile score
the percentage of scores at or below a certain score
standard score
z score; compare to scores from different normal distributions
variance
a measure of spread within a distribution (the square of the standard deviation)
standard deviation
a computed measure of how much scores vary around the mean score
correlation
a measure of the relationship between two variables
positive correlation
a correlation where as one variable increases, the other also increases, or as one decreases so does the other; both variables move in the same direction
negative correlation
a correlation where two factors vary systematically in opposite directions; one increasing as the other decreases
independent variable
manipulated factor
dependent variable
participant's factor
experiment
an organized procedure to study something under controlled conditions
quasi experiment
a research method that looks like an experiment BUT subjects are not randomly assigned to control and experimental groups (no cause and effect can be drawn)
naturalistic observation
observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation
survey
a technique for ascertaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group
case study
an observation technique in which one person is studied in depth in the hope of revealing universal principles
experimental group
group tested with a variable
control group
group that doesn't receive test variable
population
group from which samples are drawn
sample
group being tested
random selection
subjects are randomly selected from a population
random assignment
assigning experimental and control conditions by chance
experimenter bias
expectation of the person conducting an experiment which may be affect the outcome
single blind study
a study in which the participants are unaware of whether they are in the control group or the experimental group
double blind study
research method in which both the subjects and the experimenter are unaware or 'blind' to the anticipated results
demand characteristics
participants change behavior to fit their interpretation of the experiment
confounding variables
factors that cause differences between experimental group and control group, "third variable"
operational definition
precise instructions about how to measure concepts and variables
variability
degree to which data are spread out or differ
correlational coefficient
strong positive correlation: +1
statistical significance
p value; a statistical statement of how likely it is that an obtained result occurred by chance
theory
a hypothesis that has been tested with a significant amount of data
hypothesis
a claim intended to explain facts or observations
replication
process of repeating a study to increase validity of results
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