Terms associated with statistics

Statistics is the study of the collection, organization, analysis, and interpretation of data and drawing conclusions from it. It is the application of mathematical principles to the collection, analysis, and presentation of data.

Data are the values (measurements or observations) that the variables can assume. When data is collected in its original form, it is called raw data or unprocessed information. When data is ordered, it is called a data array

Variable is a characteristic or attribute that can assume different values. The variable can be independent or dependent.

An independent variable is one that can be manipulated by the researcher during the experiment while the dependent variable is the factor that is expected to be affected or influenced by the independent variable.

Two concepts of statistics are also related to the sample and population, thus parameter and statistic.

(i) Population consist of all subjects (human or otherwise) that are being studied or a universal set of subjects (human or otherwise) under consideration. For example, Tehila, a Grade 9A pupil at St Mary’s Secondary School could be drawn from a population of either Grade 9A or all Grade 9 classes at St Mary’s School. A sampleis a group of subjects selected from a population.

(ii) A Parameter is a numerical description of a population characteristic.

(iii) A Statistic is a numerical description of a sample characteristic.

Frequency: In any population two or more members may have the same value. For example, the height (to the nearest cm) of several members of a school may be the same. The number of members with the same value is known as the frequency and is generally denoted by f Frequency Distributions This is a table that summarises how often each score on a test occurs.