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probDistriCal

The Online Calculator For Probability Distributions

By W. J. Zhang and Y. H. Qi



The user manual guide and suggested citation of this page:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77
Also, click here to download the corresponding offline calculator.

Continuous Distributions Discrete Distributions

Continuous Distributions
Normal Distribution
Mean (μ):

Standard deviation (σ):

Random variable (x):



p-value (Probability that the random variable X takes a value not less than x):

P (Probability that the random variable X takes a value less than x):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

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t Distribution
Degree of freedom (n):

Random variable (x):



p-value (Probability that the random variable X takes a value not less than x):

P (Probability that the random variable X takes a value less than x):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

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F Distribution
1st degree of freedom (m):

2nd degree of freedom (n):

Random variable (x):



p-value (Probability that the random variable X takes a value not less than x):

P (Probability that the random variable X takes a value less than x):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

   Back to Top   


χ2 Distribution
Degree of freedom (n):

Random variable (x):



p-value (Probability that the random variable X takes a value not less than x):

P (Probability that the random variable X takes a value less than x):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

   Back to Top   


Exponential Distribution
Parameter (λ):

Random variable (x):



p-value (Probability that the random variable X takes a value not less than x):

P (Probability that the random variable X takes a value less than x):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

   Back to Top   


Power Law Distribution
Parameter (α):

Parameter (xmin):

Random variable (x):



p-value (Probability that the random variable X takes a value not less than x):

P (Probability that the random variable X takes a value less than x):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

   Back to Top   


Weibull Distribution
Parameter (m):

Parameter (x0):

Parameter (v):

Random variable (x):



p-value (Probability that the random variable X takes a value not less than x):

P (Probability that the random variable X takes a value less than x):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

   Back to Top   


Zhang Distribution
Parameter (α):

Parameter (β):

Parameter (γ):

Parameter (a):

Parameter (b):

Random variable (x):



p-value (Probability that the random variable X takes a value not less than x):

P (Probability that the random variable X takes a value less than x):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

   Back to Top   


Discrete Distributions
Binomial Distribution
Parameter (n):

Parameter (p):

Random variable (r):



Pr (Probability that the random variable takes the value r):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

   Back to Top   


Poission Distribution
Parameter (λ):

Random variable (r):



Pr (Probability that the random variable takes the value r):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

   Back to Top   


Negative Binomial Distribution
Parameter (K):

Parameter (P):

Random variable (r):



Pr (Probability that the random variable takes the value r):


User manual guide:
Zhang W. J., Qi Y. H. 2025. probDistriCal: The online calculator for probability distributions. Computational Ecology and Software, 15(2): 57-77

   Back to Top   


Copyright © 2025 - W. J. Zhang and Y. H. Qi (E-mail: wjzhang@iaees.org, qiyh@mail.sysu.edu.cn)
International Academy of Ecology and Environmental Sciences. E-mail: office@iaees.org
Copyright © 2009-2024. International Academy of Ecology and Environmental Sciences. All rights reserved.
Web administrator: office@iaees.org, website@iaees.org;


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