IssacJones

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# plotting in python using binomial

Hi

I am trying to learn python and graphing. Could anybody help me with the following?

I want to plot a graph of probabilities using the Binomial which I will write as B(N,n,p); where N is the total number of events, n is the number of successes and p is the probability of a success.

What I want to do is plot the probability of the n events occurring for varying N but fixed n and p.

For example, if n = 20 and p = 0.1, I would like to work out the probability of P(n=20, p=0.1) for N = 20, ... , 100.

Could someone give me the Python code which would allow me to do this?

Thanks in advance

Issac

I am trying to learn python and graphing. Could anybody help me with the following?

I want to plot a graph of probabilities using the Binomial which I will write as B(N,n,p); where N is the total number of events, n is the number of successes and p is the probability of a success.

What I want to do is plot the probability of the n events occurring for varying N but fixed n and p.

For example, if n = 20 and p = 0.1, I would like to work out the probability of P(n=20, p=0.1) for N = 20, ... , 100.

Could someone give me the Python code which would allow me to do this?

Thanks in advance

Issac

Are you searching the tool formaking graphs or you already use some?

For the combinatorics, the standard module itertools implements some generators that return combinations and permutations. See http://docs.python.org/library/itertools.html

For the combinatorics, the standard module itertools implements some generators that return combinations and permutations. See http://docs.python.org/library/itertools.html

ASKER

Hi pepr

To plot the graph I was going to use matplotlib (?)

Essentially all I'm asking is given a function, be it y = x^2, y = sin x + x^3, or whatever and an array of x values e.g. x = -2, -1, 0, 5, 10, how do I plot the graph.

I come from a C++ background, so I assumed that you could have an array of x values e.g. x[5] (for the above) from which I could then calculate the corresponding y values y[5], and then pass these into some kind of plotting routine e.g. matplotlip must have something I suspect.

Any ideas?

To plot the graph I was going to use matplotlib (?)

Essentially all I'm asking is given a function, be it y = x^2, y = sin x + x^3, or whatever and an array of x values e.g. x = -2, -1, 0, 5, 10, how do I plot the graph.

I come from a C++ background, so I assumed that you could have an array of x values e.g. x[5] (for the above) from which I could then calculate the corresponding y values y[5], and then pass these into some kind of plotting routine e.g. matplotlip must have something I suspect.

Any ideas?

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ASKER

Many thanks

ASKER

If it helps, can anybody tell me how to do the following?

(1) Using x in the range 0 to 20, plot y=x^2 and plot the graph.

(2) Is there a library function which will allow me to calculation combiations i.e. nCr values?

Thanks in advance

Issac