molbiotools
☰
Useful links Send feedback! User guide
×

Molbiotools is a collection of free online apps:

DNA Sequence Tools
Text and Data Tools
Lab Calculators
Math Calculators

Negative Binomial Distribution Calculator

Aa free online tool for calculating probabilities of events following negative binomial distribution.
Negative binomial distribution describes the probability that the x-th independent trial will be the k-th success provided each success has the same probability p:
P(X=x) = (
x-1
k-1
 ) (1-p)x-k pk
Alternatively, the distribution describes the probability of the next independent trial being the k-th success after a fixed number r of failures have occurred:
P(k, r) = (
k+r-1
k-1
 ) (1-p)r pk

x>0, k>0, x≥k, r≥0, 0<p<1; x = k + r

Clear
Calculate

Calculator

Probability of success in one trial:p =

Number of successes:k =

Calculate the probability that the x-th trial will be the k-th success:
x = , or alternatively, set the number of failures:r =
Calculate the total probability of all values x from the interval x1 - x2:
x1 = x2 =

P(X = x):

P(X ≤ x):

P(X ≥ x):

Mean: