00:01
Okay, we are told here 13 % of the population are left -handed and that means write down p of left -handed is 0 .13 which implies p of not left -handed so we'll say right -handed is 1 minus that 0 .87.
00:25
So binomial type distribution so you have success and failure, success being left -handed 0 .13, failure .87.
00:36
The sum has to be 1 every time.
00:39
At least two left -handed means 2, 3, 4, 5, 6, 4, 7 left -handed.
00:46
I could work out all those and add them all up and get the answer, but easier go backwards.
00:52
1 minus p of what you don't want to happen.
00:56
I want to get at least 2 left -handed.
00:59
I don't want 0 or 1.
01:03
Person left -handed...