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Function Reference: poisscdf

statistics: p = poisscdf (x, lambda)
statistics: p = poisscdf (x, lambda, 'upper')

Poisson cumulative distribution function (CDF).

For each element of x, compute the cumulative distribution function (CDF) of the Poisson distribution with rate parameter lambda. The size of p is the common size of x and lambda. A scalar input functions as a constant matrix of the same size as the other inputs.

p = poisscdf (x, lambda, "upper") computes the upper tail probability of the Poisson distribution with parameter lambda, at the values in x.

Further information about the Poisson distribution can be found at https://en.wikipedia.org/wiki/Poisson_distribution

Input arguments must be double, single, or an integer type; logical and character arrays are rejected. Integer input is promoted to double, so the result is always a probability. MATLAB is inconsistent here: for several of the discrete distributions it returns the result in the integer class of the input, truncating a probability to 0 or 1.

See also: poissinv, poisspdf, poissrnd, poissfit, poisslike, poisstat

Source Code: poisscdf

Plot various CDFs from the Poisson distribution

 x = 0:20;
 p1 = poisscdf (x, 1);
 p2 = poisscdf (x, 4);
 p3 = poisscdf (x, 10);
 plot (x, p1, '*b', x, p2, '*g', x, p3, '*r')
 grid on
 ylim ([0, 1])
 legend ({'λ = 1', 'λ = 4', 'λ = 10'}, 'location', 'southeast')
 title ('Poisson CDF')
 xlabel ('values in x (number of occurrences)')
 ylabel ('probability')
plotted figure