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Introductory Statistics
Found in: Page 253
Introductory Statistics

Introductory Statistics

Book edition OER 2018
Author(s) Barbara Illowsky, Susan Dean
Pages 902 pages
ISBN 9781938168208

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Short Answer

On May 11, 2013 at 9:30 PM, the probability that moderate seismic activity (one moderate earthquake) would occur in the next 48 hours in Japan was about 1.08%. As in Example 4.8, you bet that a moderate earthquake will occur in Japan during this period. If you win the bet, you win $100. If you lose the bet, you pay $10. Let X = the amount of profit from a bet. Find the mean and standard deviation of X.

Mean= Expected value =-8.812

Standard deviation =11.3696

See the step by step solution

Step by Step Solution

Step 1: Content Introduction

To find mean and deviation of X, let us first make the following table with the given information:

Step 2: Content Explanation

Mean = Expected value

μ=Sum of XP (X)

Sum of values in the fourth column of the above table


Standard deviation =Sum root of (X-μ)2P(X)=127.872+1.3961=129.2686=11.36

Therefore, there is an average loss of amount $8.81 per bet with a standard deviation of amount $11.36 in the average loss per bet in the long run.

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