00:02
And so we're told that iqs follow a normal distribution with mean of 100, standard deviation of 15.
00:08
And i wouldn't know what's the probability that a randomly selected person scores greater than or equal to 118.
00:14
So just in general, my 100 is here in the middle.
00:18
My 118 is going to be to the right of that, and i'm finding this area to the right of that value.
00:24
So i'm going to use the normal cdf function.
00:28
My lower bound is 118.
00:30
My upper bound is a really, really, really large number.
00:32
And then my mean is 100 and my standard deviation is 15, and this gives me a probability of 0 .1151.
00:41
The second part of the question says the probability that a randomly selected person scores lower than this value is 0 .25.
00:51
So again, my 100 is here in the middle.
00:53
I've got some score here to the left such that the area to the left of that score is 0 .25.
01:02
So when i know the area, and i'm solving for a value, i'm going to use inverse norm.
01:09
And 0 .25 is the area to the left...