Analysis and Approaches for IBDP Maths Ebook 1 | Page 272

Your Practice Set – Analysis and Approaches for IBDP Mathematics
Chapter
20
Binomial Distribution
SUMMARY POINTs
� Properties of a random variable X ~ B( n, p ) following binomial distribution:
1. Only two outcomes from every independent trial (Success and failure)
2. n : Number of trials
3. p : Probability of success
4. X : Number of successes in n trials
�
Formulae for binomial distribution:
�n�
r
1. P( X � r) � � �p (1 � p)
�r
�
2. E( X )
n�r
for 0 �r�
n
� np : Expected value of X
3. Var( X ) �np(1 � p)
: Variance of X
4. np(1 � p)
: Standard deviation of X
5. P( X � r) � P( X � r �1) �1� P( X � r � 1)
Solutions of Chapter 20
264
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