Binomial and Geometric Distributions in the Calculator – TI Calculators
Binomial:
Ex.: On a 10 question test, I have a 0.25 chance of answering a question correct if guessing. What is the
probability that I get four questions correct? n = 10, p = 0.25, k = 4  P(X = 4)
2nd , DISTR, 0:binompdf(
binompdf(n, p, k)
What is the probability that I get at most four correct? n = 10, p = 0.25, k = 4  P(X ≤ 4)
2nd , DISTR, A:binomcdf(
binomcdf(n, p, k)
Only for ≤. Need to manipulate
this for < or ≥.
Geometric:
Ex.: Michael has a 0.3000 batting average. He steps up to the plate. What is the probability that he gets his first
hit on his 3rd at-bat? p = 0.3, k = 3  P(X = 3)
2nd , DISTR, D:geometpdf(
geometpdf(p, k)
What is the probability that he gets a hit is at most three at-bats? p = 0.3, k = 3  P(X ≤ 3)
2nd , DISTR, E:geometcdf(
geometcdf(p, k)
Only for ≤. Need to manipulate
this for < or ≥.
Binomial and Geometric Distributions in the Calculator – HP Prime
Binomial:
Ex.: On a 10 question test, I have a 0.25 chance of answering a question correct if guessing. What is the
probability that I get four questions correct? n = 10, p = 0.25, k = 4  P(X = 4)
In home screen of
either Stats 1Var or
Stats 2Var:
*Press Toolbox
*Math 
Probability 
Density 
Binomial
Enter as:
BINOMIAL(n,p,k)
What is the probability that I get at most four correct? n = 10, p = 0.25, k = 4  P(X ≤ 4)
In home screen of
either Stats 1Var or
Stats 2Var:
*Press Toolbox
*Math 
Probability 
Cumulative 
Binomial
Enter as:
BINOMIAL_CDF
(n, p, k)
Only for ≤.
Need to
manipulate
this for < or ≥.
Geometric:
Ex.: Michael has a 0.3000 batting average. He steps up to the plate. What is the probability that he gets his first
hit on his 3rd at-bat? p = 0.3, k = 3  P(X = 3)
In home screen of
either Stats 1Var or
Stats 2Var:
*Press Toolbox
*Math 
Probability 
Density 
Geometric
Enter as:
GEOMETRIC(p,k)
What is the probability that he gets a hit is at most three at-bats? p = 0.3, k = 3  P(X ≤ 3)
In home screen of
either Stats 1Var or
Stats 2Var:
*Press Toolbox
*Math 
Probability 
Cumulative 
Geometric
Enter as:
GEOMETRIC_CDF
(p,k)
Only for ≤.
Need to
manipulate
this for < or ≥.