Difference between revisions of "SOCR EduMaterials Activities Discrete Probability examples"
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*<math> P(X \ge 1)= 1-P(X=0)=1-.7^8 </math> | *<math> P(X \ge 1)= 1-P(X=0)=1-.7^8 </math> | ||
*<math> Expected value= np = 8*.3=2.4 </math> | *<math> Expected value= np = 8*.3=2.4 </math> | ||
| − | *<math> Sd(X)= sqrt( | + | *<math> Sd(X)= sqrt(npq)</math> |
Revision as of 13:49, 23 April 2007
- Description: You can access the applets for the above distributions at http://www.socr.ucla.edu/htmls/SOCR_Distributions.html .
- Example 1:
Find the probability that 3 out of 8 plants will survive a frost, given that any such plant will survive a frost with ptobability of 0.30. Also, find the probability that at least 1 out of 8 will survive a frost. What is the expected value and standard deviation of the number of plants that survive the frost?
- Answer:
- \( X \sim b(8,0.3) \), \( P(X=3)= {8 \choose 3} 0.8^30.7^5\)
- \( P(X \ge 1)= 1-P(X=0)=1-.7^8 \)
- \( Expected value= np = 8*.3=2.4 \)
- \( Sd(X)= sqrt(npq)\)
