CODEWITHSUNDEEP
r
user1723765
user1723765

Reputation: 6409

Calculate cumulative binomial probability in R

I would like to calculate the cumulative probability of a binomial series:

a=choose(5,0)*0.5^0*0.5^5
b=choose(5,1)*0.5^1*0.5^4
c=choose(5,2)*0.5^2*0.5^3
d=choose(5,3)*0.5^3*0.5^2
e=choose(5,4)*0.5^4*0.5^1
f=choose(5,5)*0.5^5*0.5^0

cumulative=sum(a,b,c,d,e,f)

Is there any way to do this with a single command?

Upvotes: 5

Views: 9472

Answers (1)

James
James

Reputation: 66864

For cumulative probability use pbinom:

pbinom(0:5,5,0.5)
[1] 0.03125 0.18750 0.50000 0.81250 0.96875 1.00000

For individual values, dbinom:

dbinom(0:5,5,0.5)
[1] 0.03125 0.15625 0.31250 0.31250 0.15625 0.03125

And for summing cumulatively use cumsum:

cumsum(dbinom(0:5,5,0.5))
[1] 0.03125 0.18750 0.50000 0.81250 0.96875 1.00000

Upvotes: 8

Related Questions