00:01
So we'll let x be the hemoglobin level for a healthy adult female.
00:05
We're told that x then is normally distributed with a mean of 17 and a standard deviation of 0 .9.
00:17
And then we want for part a, the probability that a randomly chosen healthy female has a hemoglobin level of less than 15.
00:29
Well that is the probability that x minus the mean divided by the standard deviation is less than 15 minus the value of the mean divided by the value of the standard deviation.
00:41
And that is the probability that the standard normal then is less than negative 2 divided by 0 .9 is negative 2 .22.
00:54
And then i can look up in my standard normal table that is going to be 0 .0132.
01:06
And then for the second part, i want the probability that x is between 16 and 18, which is the probability that 16 minus 17 divided by 0 .9 is less than x minus the mean divided by the standard deviation is less than 18 minus 17 divided by 0 .9.
01:32
And that is the probability that a standard normal is between, let's see here, negative 1 divided by 0 .9, negative 1 .11, less than z, less than 1 .11...