A table in which data values are divided into either a "leaf" or a "stem." In a stem and leaf plot, the stem values appear on the vertical axis and the leaf values are listed on the horizontal axis.
A form of nonprobability sample using respondents who are convenient or readily accessible to the researcherfor example, employees, friends, or relatives
Range of the middle 50 of the values; Q3-Q1 75th percentile - 25th percentile
Anything in the survey design that influences the responses from the sample