00:01
There is given class data, so there are some intervals for the class and the frequency is given.
00:08
So we have to find the mean of this data.
00:13
So what we have to do, first of all, let's find the middle point, the midpoint for the class.
00:21
So the midpoint, which is, so 0 and 15, the middle point is, that is, so 15 minus 015 divided by 2, 7 .5.
00:32
So 7 .5 is the middle point here and the middle point for this one which is 23 .5.
00:40
And this one is 39 .5.
00:43
I just add up the lower boundary, 7 .5, to get the class the middle point.
00:51
Why? because every class, every interval has the length of 15.
00:56
I just divide by 152.
00:58
That is 7 .5...