00:01
In this problem, we are given that ferritin test, this is used to measure person's iron store and ferritin amount in women.
00:12
Let's represent that with the variable x.
00:14
This is having normal distribution such that the mean of the distribution is 89 nanograms per ml and the standard division, well that's equal to 23 nanograms per ml and we are required to compute the probability that the ferritin level in the women, this is 100 or less.
00:38
So for that, we will simply use this formula and let's get the z -score corresponding to the value 100.
00:45
So we see that this will be the probability that the z -score is less than or equal to 100 minus 89 divided by 23, which will be the probability that the z -score is less than or equal to 0 .48.
00:58
And using the z -table, we get this probability is 0 .6844.
01:04
And in the next part, we have to compute that if a woman is having ferritin level of 140, then what percentile is this? so this means that probability that x is less than 140, this will be the probability that the z -score is less than 140 minus 89 divided by 23, which will be the probability that the z -score is less than 2 .217...