00:02
Hello, so let's look at the information we have.
00:03
We have the mean incubation time to be 20 days.
00:08
So let's say this is mean 20 days, okay? there's a normal distribution and i want to first determine the 20th percentile for the information times.
00:27
The standard division has been given as one day.
00:34
So now to determine the 20th percentile.
00:37
What that means is visibly looking at the probability.
00:45
We want to get the probability of z or excuse me let me rephrase that so the way we represent the percent are that probability of z less than z is 20 percent that's 0 .2 okay, so now we need to use the z table to figure out the z value that gives this probability so from a z table the z value is negative 0 .842 now with this now we can use the z score formula to get up percentile so x is what we are looking for so that's that plus that's me right so you have x equals negative 0 .842 10 and division is 1 plus mean what is mean it's 20 so our 20th percent is going to be 19 .158.
02:00
That is our 20th percentile.
02:09
I'm just looking b.
02:11
Now b is talking about, just a second, it's talking about the incubation time that will become the middle 97%...