 Hi and welcome to our session. Let us discuss the following question. The question says, find the mean deviation about median for the following data. This is the data given to us and we have to find the mean deviation about the median. Even solving this question, we should know the steps which are involved in the calculation of mean deviation about mean. In the first step, we find the midpoint of each given class interval which is denoted by Xi and this Xi is equal to upper limit plus lower limit divided by 2. After this, cumulative frequencies are calculated, then we calculate n which is equal to summation i goes from 1 to n fi for the median classes that class interval whose cumulative frequency is equal to or just greater than n plus 1 by 2 observation. And if n is even, then median classes that class interval whose cumulative frequency is equal to or just greater than n by 2 observation. Then we calculate the median and median is equal to lower limit of median class plus n by 2 minus cumulative frequency of preceding class interval divided by frequency of median class into h. h is the width of the median class. After this, we find the deviation of each Xi from m that is h1 minus m, x2 minus m and so on. Then in the third step, we find the absolute value of each deviation and in the last step, we find the mean of the absolute values of the deviations and this mean is the mean deviation about mean that is mean deviation about mean is equal to 1 by n into summation i goes from 1 to n fi into more Xi minus m where n is equal to summation i goes from 1 to n fi and m is equal to median. So, keeping all these steps in mind, let's now begin with the solution. We will first make a table. In the first two columns, we have written the given information. We will find midpoint of each class interval. The midpoint of class interval 0 to 10 is 0 plus 10 by 2 and this is equal to 5. 10 plus 20 by 2, this is equal to 50. 20 plus 30 by 2 is 25. 30 plus 40 divided by 2 is 35. 40 plus 50 divided by 2 is 45. 50 plus 60 divided by 2 is 55. Now, we will find cumulative frequency. In the first row, we will have 6. Then we have 8 plus 6, which is 40. 14 plus 14, 28, 28 plus 16, 44, 44 plus 4, 48, 48 plus 250. We will find n. n is equal to summation i goes from 1 to 6 fi. This is equal to sum of all these frequencies that is 6 plus 8 plus 40 plus 16 plus 4 plus 2 and this is equal to 50 and 50 is even and we know that if n is even, then median class is that class interval whose cumulative frequency is equal to or just greater than n by 2 or observation. So, n by 2 is equal to 50 by 2 and this is equal to 25. Now, the class interval containing 25th item 20 to 30. Therefore, 20 to 30 is the median class. If I am median, median is equal to lower limit of median class n by 2 minus cumulative frequency of preceding class interval divided by frequency of median class into h. So, median class is 20 plus n by 2 is 25 minus cumulative frequency of preceding class interval. That means cumulative frequency of class interval 10 to 20, cumulative frequency of class interval 10 to 20 is 40. So, we have 25 minus 40 minus, sorry, divided by frequency of median class, frequency of class interval 20 to 30 is 40 into width of the median class that is 10. This is equal to 20 plus 110 by 40. This is equal to 20 plus 7.85 and this is equal to 27.85 mod xi minus n. Now, n is equal to 27.85 and in the first row value of xi is 5. So, we have 5 minus 27.85 and this is equal to minus 22.85. 15 minus 27.85 is minus 12.85 and 25 minus 27.85 is minus 2.85. Calling the same pattern we have filled other boxes. Now, we will find mod of xi minus n, absolute value of minus 22.85 is 22.85, absolute value of minus 12.85 is 12.85, absolute value of minus 2.85 is 2.85, absolute value of 7.15, 17.15 and 27.15 is 7.15, 17.15, 27.15. Now, we will find fi into mod xi minus n. 6 into 22.85 is 137.1, 8 into 12.85 is 102.8, 14 into 2.85 is 39.9, 16 into 7.15 is 114.4, 4 into 17.15 is 68.6, 2 into 27.15 is 54.3. On adding all this, we get 517.1. Summation, i goes from 1 to 6 fi into mod xi minus n is equal to 517.1. Now, we will calculate mean deviation about media. Now, this is equal to 1 by n into summation i goes from 1 to 6 fi into mod xi minus n. Now, this is equal to 1 by 50 into 517.1 and this is equal to 10.34. Hence, our required answer is 10.34. So, this completes the session. Bye and take care.