00:01
There's a 6 % rate of a disc drive failure in a year.
00:04
If all your computer data is stored on a hard disk drive with a copy on a second hard drive, what is the probability that during the year you can avoid catastrophe with at least one working drive? so we have drive 1 and drive 2.
00:19
So let's just say if the first one fails, that means 6 % rate of failure, which means 94%, it will not fail.
00:29
So we want at least one not to fail.
00:32
So either this one can not fail, and they can both not fail, or we can have this one not fail and this one will fail, or we could have this one not fail and this one will fail, so that we would multiply each of these together and then add our results.
00:50
So we'll get to the calculator part in a minute.
00:53
The same thing with three.
00:55
So we're really dealing with a binomial distribution.
00:59
If we want at least one works.
01:02
Now let's think about this.
01:03
It can get very cumbersome to go with a lot of numbers.
01:07
So we want at least one works...