00:01
Okay, we are told the space of graph sends back either ones or zeros as data, and ones are sent back one -third of the time, and zeros are sent back two -thirds of the time.
00:14
Now, if a zero is sent back, you are told there's a 0 .9 chance is correct.
00:21
In other words, getting a 0 .0 at the other end is a 0 .9 chance.
00:26
Getting the wrong result, 0 .1, sorry, 1 rather, is a 0 .1 chance.
00:34
Up here, also we have a chance of error.
00:39
And we are told that getting the correct value is only 0 .8.
00:45
So that means 0 is a 0 .2 chance.
00:53
Okay, next i'll work out each branch separately.
00:56
The first branch up here will be 1 3rd times 0 .8.
01:02
And that i'll work out on a calculator and we get four 15th as a fraction.
01:09
And then if i work out one -third times 0 .2, what i will get is 1 .15th as a fraction.
01:22
Here, if i do 2 thirds times 0 .9, i get 0 .6 or 3 -5ths.
01:31
And three -fifths i can write better as 9 over 15.
01:38
Get the same common number on the bottom all the way through.
01:42
It's easier.
01:43
And the last one, two -thirds times point one, is going to be 1 .15th.
01:50
You can then check and see you're correct.
01:53
Just add up the green numbers and we should get a total of 1.
01:58
And we do 15 -15ths.
02:01
So i know is correct...