explained by regression on the explanatory variableComplement of an event —set of all outcomes in the sample space that are not in the event
Completely randomized design —when all subjects (or experimental units) are randomly assigned to
treatments in an experiment
Conditional probability —the probability of one event succeeding given that some other event has
already occurred
Confidence interval —an interval that, with a given level of confidence, is likely to contain a population
value; (estimate) ± (margin of error)
Confidence level —the probability that the procedure used to construct an interval will generate an
interval that does contain the population value
Confounding variable —has an effect on the outcomes of the study but whose effects cannot be separated
from those of the treatment variable
Contingency table —see two-way table
Continuous data —data that can be measured, or take on values in an interval; the set of possible values
cannot be counted
Continuous random variable —a random variable whose values are continuous data; takes all values in
an interval
Control —see statistical control
Convenience sample —sample chosen without any random mechanism; chooses individuals based on
ease of selection
Correlation coefficient (r ) —measures the strength of the linear relationship between two quantitative
variables;
Correlation is not causation —just because two variables correlate strongly does not mean that one
caused the other
Critical value —values in a distribution that identify certain specified areas of the distribution
Degrees of freedom —number of independent data-points in a distribution
Density function —a function that is everywhere non-negative and has a total area equal to 1 underneath
it and above the horizontal axis
Descriptive statistics —process of examining data analytically and graphically
Dimension —size of a two-way table; r × c
Discrete data —data that can be counted (possibly infinite) or placed in order
Discrete random variable —random variable whose values are discrete data
Dotplot —graph in which data values are identified as dots placed above their corresponding values on a
number line
Double blind —experimental design in which neither the subjects nor the study administrators know what
treatment a subject has received
Empirical Rule (68-95-99.7 Rule) —states that, in a normal distribution, about 68% of the terms are