Meaning of raw data: Raw data or primary data are collected directly related to their object of study Univariate Frequency Distribution: 1. When data is classified on the basis of single variable, the distribution is known as univariate frequency distribution. 2. It aims to make description about the particular variable. 3. It is also known as one-way frequency distribution. 4. For example, height of students in a class. Bivariate Frequency Distribution: 1. When the data is classified on the basis of two variables, the distribution is known as bivariate frequency distribution. 2. It aims to determine the empirical relationship between the two variables. 3.  It is also known as two-way frequency distribution. 4.  For example, height and weight of students in a class.