 Hello friends and how are you all doing today? The question says, find the mean of the following frequency distribution by step deviation method. Now here we are given the class interval and frequencies as 0 to 10, 10 to 20 and so on and respective frequencies are 7, 10, 15, 0, 8 and 10. So let us start with our solution. Now for step deviation method we first have to rewrite the given class interval and frequency again. That is 0 to 10, 10 to 20 and so on. Now the next step is to find out the mid value that we see as x. It is the mid value of the class interval that is 5, 15, 25, 35 and then 45. Further next step is to subtract the assumed mean. Let us assume a number from this x as a. So we need to subtract the assumed mean from each x that we have found out here. That will be minus 20 minus 10, 0, 10, 20. Now the next step is to find out ui. That is x minus 25 upon the number that is common to all these term that is 10. All these are multiples of 10. So we have minus 2, minus 1, 0, 1 and 2. And finally we need to find out the value of fui. So it is 7 into minus 2 that is minus 14, 10 into minus 1, minus 10 and so on like this. We need to add all these that is 28 minus 24 that comes out to be 4 and we need to find out the value of the frequency that comes out to be. Now the formula for mean is a that is assumed mean plus h into 1 upon n summation where i starts from 1 till 5 fi ui. Now we need to substitute the value a is 25 that we have assumed. h is the number by which we have divided x i minus 25 that was 10 into 1 upon n that is 5 sorry that is 50 into summation of fi ui that is coming out here as 4. So we have 25 plus 4 upon 5, 125 plus 4 upon 5, 129 upon 5 that comes out to be 25.8. So the value of mean by step deviation method is 25.8 right. So this completes the session hope you understood the whole concept well do take care of all your calculations write your formula well and enjoy have a nice day.