00:01
For this problem, the first step that we'll want to take is to find the standard normal random variable, or a standard normal score, such that only 15 % of the standard normal distribution is greater than it.
00:13
So i didn't mean to make that z dot.
00:16
Probability of big z greater than little z is 0 .15.
00:24
Equivalently, probability of z less than or equal to little z would be equal to 0 .85.
00:32
So to find this, a little z value, i'll go to a standard normal distribution, or cumulative distribution table.
00:41
So we want roughly 0 .85 to the left.
00:43
Here we have 0 .8508, which is pretty close.
00:47
That is at a z score of 1 .04.
00:50
So that means that this value, such that only 15 % of the values will be greater than it, will be 1 .04 standard deviations greater than the mean...