http://www.ck12.org Chapter 4. Probability Distributions
4.4 Binomcdf Function
Here you’ll learn how to use the binomcdf function on a Texas Instruments graphing calculator to solve for binomial
probabilities.
Every time you’re late for school it seems like you get stuck in traffic. The probability of getting stopped by a
red light at a particular intersection is 28%. If you randomly pass through the intersection 30 times, what is the
probability that you get stopped by a red light more than 5 times?
Watch This
First watch this video to learn about the binomcdf function.
MEDIA
Click image to the left for more content.CK-12 Foundation: Chapter4BinomcdfFunctionA
Then watch this video to see some examples.
MEDIA
Click image to the left for more content.CK-12 Foundation: Chapter4BinomcdfB
Guidance
Thebinomcdf functionon the TI-84 calculator can be used to solve problems involving the probability of less
than or equal to a number of successes out of a certain number of trials. For example, if you wanted to know the
probability of less than or equal to 45 successes out of 100 trials, you could use the binomcdf function. Just like
when computing the probability manually with paper and pencil, you also have to know the probability of success
for any particular trial in order to find the answer. The syntax for the binomcdf function is binomcdf(n,p,a), where
nis the number of trials,pis the probability of success for any particular trial, andais the number of successes.
Example A
A local food chain has determined that 40% of the people who shop in the store use an incentive card, such as air
miles. If 10 people walk into the store, what is the probability thatat mosthalf of these will be using an incentive
card?
There are 10 trials, son=10.