00:01
Okay, we are told we have here a poisson distribution and the average rate is four patients per hour or four people per hour.
00:10
I want to work out a chance of exactly two in any given hour.
00:15
And for this, you must have a calculator.
00:18
The ti -84 plus is the most commonly one used.
00:23
So what you do is you find the function called poisson pdd.
00:33
On the calculator.
00:36
To do that press second the blue button so second followed by vars v -a -r -s on the right just below the arrow keys that brings up the menu or distributions and you can't see it yet but go down with the arrow key past number nine at the bottom and eventually you write will arrive at item d press on pdf so press enter and the input you will see there is this just mu and x.
01:11
So two number input, mu and x.
01:16
Now, mu is going to be the mean rate per hour, the average per hour, which here is your code is four.
01:28
The x value is the two.
01:30
I want exactly two in the one hour period.
01:34
So x is two.
01:34
And that just select paste then press enter again and we get 0 .1465 they want three places so 147 is the first one now next we have at least two in one hour which means two three four five six and so on so that will be a certain event minus p of zero people coming or one person coming.
02:16
So at least two is certain unless you get zero or one.
02:22
And to work out zero or one, i could do it the same way as above.
02:27
Plus on pdf for zero plus on pdf for one...