00:01
There is given a normal distribution for this question.
00:03
So the mean was given here, which is, so the mean, which is 5 .8%.
00:10
We can write at 0 .058.
00:13
And the portfolio has the 77%.
00:17
So if the portfolio has the 77 %, let me just define the standard division as the sigma here.
00:25
I can define the random variable x, which is normally the derivative, 0 .0 .58, and the standard division.
00:32
If the portfolio has the probability of or the ratio of 70%, so that means the random variable x should be greater than 0, which was given as 77%, you can write at 0 .77.
00:46
And to get this probability, first of all, let me just graph the situation here.
00:52
So the mean score here, which is 0 .058, and the 0 is over here.
00:59
So the probability of this region, which is 0 .0 .0.
01:02
077.
01:03
Sorry, the axis greater than 0, which is this region here, this is 0 .77.
01:09
To get the probability of this case or this variable here, so to get the standard division, first of all, we need to get the area of this shaded region.
01:20
So the probability of axis less than 0, which is 1 minus the probability of axis greater than 0.
01:25
This is 1 minus 0 .77, which is equal to 0 .23.
01:30
I'm going to find the z score for 0...