00:01
Okay, we have here seven questions.
00:02
Each one has five choices and you guess.
00:06
So that means p of being correct on any given question, you have one chance out of five, 4 .0 .2, which means, of course, p of wrong must be 4 out of 5 or 0 .8.
00:27
So this then is a binomial type question where you have success and failure, success, failure point eight.
00:36
And i want to work out.
00:39
If i answer seven questions, the chance are getting less than five correct.
00:46
P of then 0, 1, 2, 3, or 4, correct.
00:54
So less than 5, 4, 3, 1, or 0, correct.
00:58
And for this, i need a calculator.
01:01
The ti 84 plus is the one to use.
01:05
And the function you need, which is called binomial or binom cdf.
01:14
The c stands for cumulative.
01:16
It will add up 0, 1, 2, 3, 4 in this case.
01:21
Now to find that function, what you do is press second, the blue button, second, followed by vars, v -a -r -s, on the right, just below the arrow keys.
01:33
That brings up the menu for distributions...