00:01
This question we have given n is equal to 400.
00:07
The average sample age is given as x bar is equal to 30.
00:16
The standard deviation is given as 4 .4.
00:21
And using this information, first we have to calculate the 95 % consistent interval for the average age of all the patients.
00:32
So here for this first we will find the value of sigma x bar.
00:39
This is equal to sigma divided by under root of n.
00:43
So using this formula we can write it as sigma x bar is equal to 4 .4 under root of 400.
01:04
So this is equal to 4 .4 divided by 20.
01:12
So if we simplify this then we'll get it as 0 .22.
01:18
Now as we have given here, alpha is equals to 1 minus 0 .95 which is equal to 0 .5.
01:38
Therefore alpha divided by 2 will be 0 .0 to 5.
01:44
Therefore, z alpha divided by 2 will be z 0 .0 to 5.
01:51
So using that table we can write it as 1 .96.
01:56
Now we know the formula for marginal error, that is e is equal to z alpha divided by 2 multiplied with sigma x bar.
02:09
So if we substitute both the values here, then we'll get the marginal error.
02:13
E is equal to 1 .96 multiplied with 0 .22...