In this tutorial you will learn how to use the binomial
CDF function on the TI 84. For a binomial experiment
n stands for the fixed number trials, p stands for probability of success,
and r stands for the number of successes.
Let's consider this example: a surgical technique is performed on seven patients.
You are told there is a 70% chance of success.
Find the probability that the surgery is successful
for less than five patients, using technology.
The solution
shows that we first note
that the number of trials here n is 7
since the technique is performed on seven patients.
The probability of success is .70 since we're told there's a 70 percent
chance of success.
We were asked to find probability that the number sucesses is less
than five. This is also
finding the probability that there are no successes
plus one sucess plus 2 successes
plus 3 successes plus 4 successes.
The answer to this is: is
.353 or a 35.3 percent chance.
Let's find out how to find that answer using
the TI. To do this
we locate the "distribution" function on a TI.
We hit second "distribution"
and we scroll down until we find
binomial CDF. Notice that there's a binomial PDF that
is for exactly r successes, and the binomial CDF function
is for a less than statement involving
r, so less than or equal to r
number of successes. We select binomial CDF
and hit "enter" And we first enter
n, which is the number trials, in this problem we have 7.
We put a comma
and enter in the probability of success
in this problem we had .7,
next we hit comma, and we will enter in up to the number of succeses in this
case up to 4 (and including 4.)
So this function accumulates the probabilities starting at zero all the way up to and including
r success. In this case we want less than five
so we will use 4 as the
up to and including value. So we close the parentheses
and hit enter. Here we see the answer
is .35 and if you round to the third place value
you would use .353.
