Bar graph: A graph using parallel bars (vertical or horizontal) that are proportional lengths to represent data.

BIA/OIEP: The Office of Indian Education Programs (OIEP) is a service organization that is a part of the Bureau of Indian Affairs (BIA), an agency within the Department of the Interior. OIEP is devoted to providing quality education opportunities for American Indian people. OIEP's mission is to serve children and their families from birth through life, working in partnership with Indian tribes, families, communities and American Indian education organizations. The OIEP fulfills its mission through its organization located in Washington, D.C. as well as in 25 offices throughout the United States. The 185 elementary and secondary schools funded by the federal government provide an education program to 50,000 students from birth through grade 12. The Office of Indian Education Programs also operates two colleges and funds 25 colleges operated by tribes and tribal organizations.

Cohort analysis: A study of a population with a common characteristic over a period of time, e.g., a birth cohort consists of all those born in a given year.

Frequency: The number of times a phenomenon occurs within a given interval.

Line graph: A graph that uses line segments to show how data change over a period of time.

Line of best fit: A line drawn through the points of a scatterplot that best estimates the relationship between the two variables.

Longitudinal analysis: Studies in which variables relating to an individual or group of individuals are assessed over a period of time.

Mean: The sum of all the results included in the sample divided by the number of observations

Negative relationship/correlation: A relationship between two data sets of variables in which one set of data decreases as the other set of data increases.

Percentage: An amount representing a fraction or ratio, with 100 understood as the denominator. Percentages signify a proportion in relation to the whole.

Positive relationship/correlation: A relationship between two data sets of variables in which both sets of data increase together.

Reliability vs. Validity: Although reliability is a desired quality, it provides no assurance that a measure will give the desired results. Little is gained if measures, or assessments, consistently give the wrong information. We need assurance that the measure is valid, or measures precisely what is intended. Of the two qualities, reliability and validity, validity is the more important.

Scatterplot: A graphical technique used to analyze the relationship between two variables. The graph will show a series of data points, or "dots," each representing a case or person with values on two variables. Possible relationships are discovered by evaluating the resulting shape of the plot, made up of the entire sample of cases or persons represented.

X-axis: The horizontal axis of a two-dimensional plot, or graph.

Y-axis: The vertical axis of a two-dimensional plot, or graph.