00:01
We're looking at a poisson distribution.
00:03
The error rate is 26 per thousand lines of code.
00:07
So lambda is 26, and this is per thousand lines.
00:13
But a, we're looking at 250 lines of code.
00:17
We want the probability of no errors.
00:19
I'm going to use the poisson formula.
00:22
Probability of exactly x errors is lambda to the power of x, e to the minus lambda, over x factorial.
00:31
Here, we're looking at 200.
00:33
50 lines, not 1 ,000, so i'd better divide this by 4.
00:37
So there are on average 6 .5 errors per 250 lines of coat.
00:44
We want probability x equals 0, so we want 6 .5 to power of 0, which is just 1.
00:50
Over 0 factorial, it's just 1.
00:52
E to the minus 6 .5.
00:55
And that is 0 0 .15.
01:04
Upby.
01:05
Probability of exactly 29 in a thousand.
01:08
Lines.
01:09
So lambda is 26.
01:13
Probability x is 29 is 26 of the power of 29, e to the minus 26, over 29 factorial.
01:27
Not very pleasant numbers, but i calculate it's fine with this.
01:36
And that is 0 .0 .6 to 5 to 4 decimal places...