 Hello and welcome to the session. In this session, we are going to discuss what a histogram is and how it is drawn. Histogram is a biograph which can be used to visually show frequency of occurrence of a continuous variable such as the height of students in a grade along the vertical axis and the variable itself along the horizontal axis while drawing the histogram for a particular set of values of a continuous variable. We use the following method. First, take the upper most and lower most values of the continuous variable and find the range. Divide this range of values into equal intervals with no spacing between them. Since the variable is continuous that is the upper limit of an interval should be equal to the lower limit of the next interval. Thirdly, find out how many readings of the continuous variable are there per interval. This is the frequency of occurrence per interval. The intervals are 0 to 5 to 10, 10 to 15 and so on. The value 5 will be included in to 10 and not in 0 to 5 that is the interval 5 to 10 will have values from 5 to less than 10 and in this way we prepare a frequency distribution table. Next, mark the intervals of the continuous variable on the horizontal axis with a uniform scale. The values on the axis should be the upper limit of data points and if the scale does not start at the origin we shall show it by a kink or a zigzag curve then mark the frequencies on the vertical axis with a uniform scale then we shall construct rectangles by taking intervals on the x axis as their base and frequency that is the number of readings per interval as their height the area of each rectangle should be proportional to the class frequency with a constant coefficient of proportionality for all the classes. If the class widths are equal then choosing the height proportional to class frequency is equivalent to area proportional to class frequency. Let us take an example for this draw a histogram to represent the following data the table below shows the height in centimeters of 50 students in a class here the distribution is given such that there are six students whose height is from 135 to less than 140 centimeters four students whose height is from 140 to less than 145 centimeters 10 students whose height is from 145 to less than 150 centimeters 18 students whose height is from 150 to less than 155 centimeters 8 students who'd heighted from 155 to less than 160 centimeters. First students who'd heighted from 160 to less than 165 centimeters. To draw this histogram, we are already being given a frequency distribution table. So we can skip the first three steps and start with the fourth step. Now we take height along the horizontal axis and number of students along the vertical axis. On the horizontal axis, mark off the frequency intervals showing the range that is 135, 140, 145, 150, 155, 160 and 165. On the vertical axis, take the uniform scale as 2, 4, 6, 8, 10, 12, 14, 16 and 18. And then mark off frequencies corresponding to each interval that is... There are six students whose height is from 135 to less than 140 centimeters. So we have... There are four students whose height is from 140 to less than 145 centimeters. There are ten students whose height is from 145 to less than 150 centimeters. There are 18 students whose height is from 150 to less than 155 centimeters. There are eight students whose height is from 155 to less than 160 centimeters. And there are four students whose height is from 160 to less than 165 centimeters. All the intervals are of the same width and have no space between each other. As the intervals start from 135, a cube is made near the origin. From the graph, we can see that the maximum number of students have height between 150 to 155 centimeters. Here, the maximum number of students have height between 150 to 155 centimeters. This completes our session. Hope you enjoyed this session.