 Hi and welcome to the session. Let us discuss the following question. Question says, the table below shows the daily expenditure on food of 25 households in a locality. This is the given table. Find the mean daily expenditure on food by a suitable method. First of all, let us understand step deviation method for finding the mean. According to this method, mean is equal to a plus h multiplied by summation f i u i upon summation f i. Now in this formula, x bar is the mean, a is assuming h is class size, f i is frequency, u i is equal to x i minus a upon h. Where x i is the class mark of the interval or we can say it is the midpoint of the given interval, a is the assuming and h is the class size. Now we will use this formula as our key idea to solve the given question. Let us now start with the solution. First of all, let us rewrite the data given in the question. We are given daily expenditure on food and number of households. First of all, let us find out class mark for every class interval or we can say we will find out midpoint of every class interval. Let us recall that class mark is equal to upper class limit plus lower class limit upon 2. So 150 plus 100 upon 2 is 125. So here we can write 125. Similarly, 200 plus 150 upon 2 is equal to 175. Midpoint of this class interval is equal to 2 to 5. Midpoint of this interval is equal to 275 and midpoint of this interval is equal to 3 to 5. Now the next step is to choose one among the x i's as the assuming mean and denote it by a. Now let us assume that 125 is the assuming mean and we will denote it by a. Now we will find the difference between assuming mean that is a and each of the x i's. That is we will find the deviation of assuming mean from the x i's. We know deviation is denoted by di and it is equal to xi minus a. Now here clearly we can see x1 is equal to 125 and a is also equal to 125. So di1 is equal to x1 minus a that is 125 minus 125 is equal to 0. So here we can write 0. Now here clearly we can see x2 is equal to 175 and value of a is equal to 125. So deviation that is d2 is equal to 175 minus 125 which is further equal to 50. So here we can write 60 similarly here x3 is equal to 225 and a is equal to 125. So x3 minus a is equal to d3. Now 225 minus 125 is equal to 100. So 100 is equal to d3. So here we can write 100. Similarly we can find deviation for this x i. We know 275 minus 125 is equal to 150 and 325 minus 125 is equal to 200. So here the deviation is equal to 200 and here it is equal to 150. Now some key idea we know ui is equal to xi minus a upon h where h is the class size and we also know that xi minus a is equal to di. So we can write ui is equal to d upon h. We know class size is equal to upper class limit minus lower class limit. So we get class size that is h is equal to 50. Clearly we can see 150 minus 100 is equal to 50. Now we will divide all these values by 50. Or we can say we will divide all these values by class size. Now we know 0 divided by 50 is equal to 0. 50 divided by 50 is equal to 1. 100 divided by 50 is equal to 2. 150 divided by 50 is equal to 3. 200 divided by 50 is equal to 4. Now we know number of households represent the frequency. So we will denote it by f i. Now we will find out the product f i ui. 4 multiplied by 0 is equal to 0. 5 multiplied by 1 is equal to 5. 12 multiplied by 2 is equal to 24. 2 multiplied by 3 is equal to 6. And 2 multiplied by 4 is equal to 8. Now we will find out summation f i. We know summation f i is equal to sum of all these frequencies. And we also know that this is the data for 25 households. So we get summation f i is equal to 25. Now we will find out summation f i ui. It is equal to sum of all these products. And sum of all these products is equal to 43. From key idea we know name is equal to a plus h multiplied by summation f i ui upon summation f i. Now substituting corresponding values of a h summation f i ui and summation f i in this formula we get name is equal to 1 to 5 plus 60 multiplied by 43 upon 25. Now this implies name is equal to 1 to 5 plus 86. Surely we can see 25 will cancel 50 by 2 and 2 multiplied by 43 is equal to 86. Now this further implies that name is equal to 211. So we get name value expenditure on food is equal to rupees 211. So this is our required answer. This completes the session. Hope you understood the solution. Take care and have a nice day.