binomial.py

import math
from combination import CombinationCalc

class BinomialCalc(object):
    def binomial_calc(self, success_prob, trials, successes):
        result = []
        comb = CombinationCalc()
        if success_prob < 0 or trials < 0 or successes < 0:
            print 'None of the numbers can be negative.'
            return
        elif successes > trials:
            print 'The number of success cannot be larger than the number of trials.'
            return
        else:
            try:
                #X = number of successes
                equal = (comb.calc_combination(trials, successes)) * math.pow(success_prob,successes) * math.pow(1 - success_prob, trials - successes)
                result.append(equal)

                #X < number of success
                less = 0
                for i in range(int(successes)):
                    less += (comb.calc_combination(trials, i)) * math.pow(success_prob, i) * math.pow(1 - success_prob, trials - i)
                result.append(less)

                #X <= number of successes
                result.append(less + equal)

                #X > number of successes
                result.append(1 - (less + equal))

                #X >= number of sucesses
                result.append(equal + (1 - (less + equal)))

                #round all numbers to fourth decimal place
                for i in range(len(result)):
                    result[i] = round(result[i], 4)

            except:
                print 'An error occurred. Enter only numbers for the parameters. Binomial'
                return

        return result

# bin = BinomialCalc()
# print bin.binomial_calc(0.5, 5.0, 3)