00:01
So, we have given that standard deviation for our sample consisting n numbers, s is equal to under root summation i is equals to 1 to n, xi minus x mean whole square and this whole divided by n minus 1.
00:22
Now, let this be equation 1.
00:24
So, here the sample mean is summation of i is equals to 1 to n, xi divided by n.
00:36
So, now from first equation, we can say that s is equal to under root summation i is equals to 1 to n, xi square plus x mean square minus 2 xi x mean.
00:59
So, this whole divided by n minus 1.
01:02
So, now taking this summation inside the bracket, we will get under root summation i is equals to 1 to n, xi square plus summation i is equals to 1 to n, x2 x mean square minus 2 summation i is equals to 1 to n, xi will have mean here and this whole divided by n minus 1.
01:41
Again, this mean is summation xi divided by n.
01:49
So, we can say that here under root or we can say summation i is equals to 1 to n, xi is equals to n mean...