00:01
And this problem we are told that the state senator believes that 25 % of all senators will strongly support a proposal.
00:06
This means p is 0 .25.
00:11
Now, five senators are approached at random, so n is 5.
00:15
And so this is a binomial, and so we have the probability of that is 5 choose x times 0 .25 to the x times 0 .75 to the 5 minus x.
00:28
And so we have just constructed our binomial distribution.
00:34
Part a, we want to find the probability at least one will strongly support the proposal.
00:39
So the probability x is greater than equal to 1.
00:41
This is the exact opposite of the probability of 0.
00:46
So we're just going to take 1 minus 0 using our complement law.
00:51
Finding the probability of 0 just means plugging in 0 for x.
00:55
This is 1 minus 5 to 0 times 0 .25 to the 0 times 0 .75 to the 5 minus 0.
01:06
And so this is 1 minus 0 .75 to the 5th...