Support the Monkey! Tell All your Friends and Teachers

Help / FAQ



Example Two dice are thrown. Find the mathematical expression of the sum of the points obtained.

Solution : Let X = sum of points obtained.

Their corresponding probabilities are

P (Xi) =

Now the expected sum of points is,

E (x) =

\ E(x) = 7


Example Given the following probability distribution .

x :    0,     1,       2,          3,    4,       5,    6,          7

Pi :    0,    2l ,    2 l ,    l,    3l,    l2,    2 l2 ,     7l2 + l

Find (1) l (2) Evaluate P (x 5) (3) Evaluate P (x < 4)

Solution : (1) We know that

Therefore, 0 + 2l + 2l + l + 3l + l2 + 2l2 + 7l2 + l = 1

10l2 + 9l - 1 = 0

10l2 + 10l - l - 1 = 0

l = 1/10 or l = -1 (discarded)

(2) P (x 5) = P (5) + P (6) + P (7)

= l2 + 2l2 + 7l2 + l

= 10l2 + l

=

(3) P (x < 4) = P (3) + P (2) + P (1) + P (0)

= l + 2l + 2l + 0

= 5l

= 5

= 0.5

[next page]

Index

7. 1 Introduction
7.2 Trial
7.3 Sample Space
7. 4 Definition of Probability
7. 5 The Laws of Probability
7. 6 Conditional Probability
7. 7 Theoretical Distribution
7. 8 Binomial Distribution
7. 9 Normal Distribution
Chapter 8





All Contents Copyright © All rights reserved.
Further Distribution Is Strictly Prohibited.


Search:
Keywords:
In Association with Amazon.com