Explain the dimensions of descriptive statistics in special education

Descriptive statistics mainly used for a group of people's numerical data such as percent, average , measures of test scores and number of hours working etc in a particular classroom setting. In this, ->variable(x) used for measurable characteristics. -> population(X) used for all subjects or objects. ->Parameter is used for measurable characteristics of a population. ->Sample used for a smaller group of subjects. -> Frequency graph used for picture depicting the number of times an event occurred. ->Bar graph used to mention the number of blocks or length representing the frequency of occurrence. ->Mean used to calculate intermediate value between several other numbers in a group. Using all or some of the above, reliability and validity measured.