00:01
In this question using data we can present the table as class, here it will be frequency, here we can write mid value and here we can write f x and it will be f x square.
00:20
Now we can put the value class will be 60 to 69, 70 to 79, 80 to 89 and 90 to 99.
00:33
The frequency will be 3, 15, 17 and 5, mid value will be 64 .5, 74 .5, 84 .5 and 94 .5, f x will be 193 .5, 1117 .5, 1436 .5 and it will be 472 .5, f x square will be 12480 .75, it will be we can write here 83253 .75, it will be 121384 .25 and finally it will be 44651 .25.
01:36
Now summation of f x we can write here will be equals to 3220 and summation of f x square will be we can write here 261770.
01:53
Also we have been given n equals to we can write here it will be frequency total 40.
01:58
Now from this we can calculate sample standard as we can write here as will be equals to under root we can write here summation of f x square minus summation of f x whole square divided by n whole divided by n minus 1...