A graphed cluster of dots, each of which represents the values of two variables
A sampling scheme that biases the sample in a way that gives a part of the population less representation than it has in the population
Bias introduced to a sample when individuals can choose on their own whether to participate in the sample
Uses sample data to test hypotheses about the shape or proportions of a population distribution. The test determines how well the obtained sample proportions fit the population proportions specified by the null hypothesis.