| correlation | Exists when two different measures of the same people, events, or things vary together; the presence of a correlation makes it possible to predict values on one variable by knowing the values on the second variable.
|
 |
|
|
| correlational research | Research whose goal is to identify predictive relationships among naturally occurring variables.
|
|
|
|
| correlation coefficient | Statistic indicating how well two measures vary together; absolute size ranges from 0.0 (no correlation) to 1.00 (perfect correlation); direction of covariation is indicated by the sign of the coefficient, a plus (+) indicating that both measures covary in the same direction and a minus (-) indicating that the variables vary in opposite directions.
|
|
|
|
| cross-sectional design | Survey research design in which one or more samples of the population are selected and information is collected from the samples at one time.
|
|
|
|
| interviewer bias | Occurs when the interviewer tries to adjust the wording of a question to fit the respondent or records only selected portions of the respondent’s answers.
|
|
|
|
| longitudinal design | Research design in which the same sample of respondents is interviewed (tested) more than once.
|
|
|
|
| nonprobability sampling | A sampling procedure in which there is no way to estimate the probability of each element’s being included in the sample; a common type is convenience sampling.
|
|
|
|
| population | Set of all the cases of interest.
|
|
|
|
| probability sampling | Sampling procedure in which the probability that each element of the population will be included in the sample can be specified.
|
|
|
|
| questionnaire | A set of predetermined questions for all respondents that serves as the primary research instrument in survey research.
|
|
|
|
| representativeness | A sample is representative to the extent that it has the same distribution of characteristics as the population from which it was selected; our ability to generalize from sample to population is critically dependent on representativeness.
|
|
|
|
| response bias | Threat to the representativeness of a sample that occurs when some participants selected to respond to a survey systematically fail to complete the survey (e.g., due to failure to complete a lengthy questionnaire or to comply with a request to participate in a phone survey).
|
|
|
|
| sample | Something less than all the cases of interest; in survey research, a subset of the population actually drawn from the sampling frame.
|
|
|
|
| selection bias | Threat to the representativeness of a sample that occurs when the procedures used to select a sample result in the over- or under-representation of a significant segment of the population.
|
|
|
|
| simple random sampling (random selection) | Type of probability sampling in which each possible sample of a specified size in the population has an equal chance of being selected.
|
|
|
|
| social desirability | Pressures on survey respondents to answer as they think they should respond in accordance with what is most socially acceptable, not in accordance with what they actually believe.
|
|
|
|
| stratified random sampling | Type of probability sampling in which the population is divided into subpopulations called strata and random samples are drawn from each of these strata.
|
|
|
|
| successive independent samples design | Survey research design in which a series of cross-sectional surveys is done and the same questions are asked of each succeeding sample of respondents.
|