Experimentation
a research method in which an investigator manipulates one or more factors to observe the effect on some behavioral or mental process
experiment
numerical data used to measure and describe characteristics of groups. includes measures of central tendancy and measures of variation
desctriptive statistics
A graphed cluster of dots, each of which represents the values of two variables
Scatterplot
a measure of the extent to which two factors vary together, and thus of how well either factor predicts the other.
correlation
The extent to which a test or experiment measures or predicts what it is supposed to
Validity
the group exposed to the treatment/independent variable
experimental group
the most fequently occuring scores in a distrabution
mode
A representation of scores that lack symmetry around their average value
Skewed Distribution
a statistical index of the relationship between two things (from -1.00 to +1.00)
correlation coefficient
In an experiment, the factor that is manipulated; the variable whose effect is being studied
Independent Variable
the group not exposed to the treatment/independent variable
control group
the arithmetic average of a distribution, obtained by addingthe scores and then dividing by the number of scores
mean
a computed measure of how much scores vary around the mean score
standard diviation
perciving a relationship where none exist , or perciving a stronger-than-actual relationship.
illusory correlation
In an experiment, the outcome that is measured; the variable that may change when the independent variable is manipulated
Dependent Variable
assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between groups
random assignment
the middle score in a distribution; half the scores are above it and half are below it
median
a symmetrical, beel-shaped curve that discribes the distribution of many types of data; most scores fall near the mean and fewer and fewer near the extremes
normal curve
the tendancy for extreme or unusual scores or events to fall back (regress) towards the average.
regression toward the mean
A factor other than the factor being studied that might influence a study's results
Confounding Variable
an experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the placebo. commonly used in drug evaluation studies
double-blind procedure
the diffrence between the highest and lowest scores in a distribution
range
a bar graph depicting a frequency distribution
histrogram
experimantal results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent.
placebo effect
Anything that can very and is feasible and ethical to measure
Variable