SOCR EduMaterials Activities Discrete Probability examples
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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? | 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:''' | * '''Answer:''' | ||
| - | <math> X \sim b(8,0.3) </math>, <math> P(X=3)= {8 \choose 3} 0.8^30.7^5 </math> | + | *<math> X \sim b(8,0.3) </math>, <math> P(X=3)= {8 \choose 3} 0.8^30.7^5</math> |
| + | *<math> P(X \ge 1)= 1-P(X=0)=1-.7^8 </math>. | ||
| + | *<math> Expected value= np = 8*.3=2.4</math> | ||
Revision as of 18:32, 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:
, 
.
- Expectedvalue = np = 8 * .3 = 2.4
