SOCR EduMaterials Activities Discrete Probability examples
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(Difference between revisions)
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*<math> X \sim b(8,0.3) </math>, <math> P(X=3)= {8 \choose 3} 0.3^30.7^5</math> | *<math> X \sim b(8,0.3) </math>, <math> P(X=3)= {8 \choose 3} 0.3^30.7^5</math> | ||
*<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> E(X) | + | *<math> E(X) = np = 8 \times 0.3=2.4 </math> |
*<math> Sd(X)= \sqrt{npq}</math> | *<math> Sd(X)= \sqrt{npq}</math> | ||
* '''Example 2:''' | * '''Example 2:''' |
Revision as of 23:23, 23 April 2007
- Description: You can access the applets for the 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:
- ,
- Example 2:
If the probabilities of having a male or female offspring are both 0.50, find the probability that a familiy's fifth child is their first son.
- Answer:
- 0.505
- Example 3:
- a. ,
- b. ++
- Example 4:
- 0.740.3
- Example 5:
- Example 6:
- a. ,
- b. P(X = 0) = 1 − 0.999 = .001
0.001 = 0.1n n = 3