 Hello and welcome to the session. In this session we shall discuss the concept of bivariate data and its relationship with population. Suppose we want to find the relationship between the marks of students in mathematics and their attendance in class. For this we need to collect data. For collecting data we need not see the marks in attendance of each student in the class. We will randomly select some students and note their marks and attendance in the mathematics class. Then we will analyze this data and we will draw our conclusion. Suppose we chose 9 students then we noted their attendance and marks in mathematics and we got this table. Here we can see that we have two series one representing marks and the other showing attendance. So it is a bivariate data showing relationship between two variables say x representing marks and y representing attendance. We want to find the relationship between the marks of students in mathematics and their attendance in class but we chose only 9 students. Thus the set of all the students in mathematics class form the population and the randomly chosen students from the mathematics class form the sample of the population. Thus we define a population is any entire collection of people, animals, plants or things from which we may collect data. It is the entire group we are interested in which we wish to describe or draw conclusions about and a sample is a group of units selected from a larger group that is the population. Thus when two characteristics are measured for each object in a sample or population the resulting data are bivariate. Bivariate data are paired data that give information about two different characteristics or attributes or variables of the elements in a sample or population. We should note that a bivariate data can be both numerical and categorical. Thus in this session we have learnt the concept of bivariate data and its relationship with population. This completes our session. Hope you enjoyed this session.