NCJ Number
81175
Date Published
Unknown
Length
0 pages
Annotation
Part of the Criminal Justice Analysis course, this videotape presents the module which focuses on basic descriptive statistics and the use of tables, graphs, and charts.
Abstract
Statistics are seen as a way to narrow a problem to manageable proportions. Objectives of the module are to understand different levels of measurement, compute and interpret some statistics that can be used to describe the data, and construct and interpret graphic displays of data. A good measurement rule provides for an exhaustive assignment, a mutually exclusive assignment, validity, and reliability. Measurement scales are classified as qualitative or quantitative. Examples of qualitative measurements are sex, race, type of crime, and type of weapon. Quantitative data include such examples as ranks in a law enforcement agency, time, temperature, age, and years of education. In all these cases, data are placed in mutually exclusive and exhaustive categories and, in the case of quantitative data, are placed in some kind of continuum. The module explains such statistical terms as mean, median, mode, standard deviation, pecent change, and frequency and percent tables. Also discussed are pie charts, bar graphs, histograms, frequency polygons, and time charts. For the instructor's guide to this course, see NCJ 81170. For other videotaped sessions, see NCJ 81171-4, 81176-82, and 81186.