SOCR EduMaterials Activities Discrete Probability examples
From Socr
(Difference between revisions)
Create90215 (Talk | contribs) |
Create90215 (Talk | contribs) |
||
Line 21: | Line 21: | ||
**b. <math>P(X\ge 2)= {4 \choose 2} 0.8^2 0.2^2+{4 \choose 3} 0.8^3 0.2^1+{4 \choose 4} 0.8^4=0.9728</math> | **b. <math>P(X\ge 2)= {4 \choose 2} 0.8^2 0.2^2+{4 \choose 3} 0.8^3 0.2^1+{4 \choose 4} 0.8^4=0.9728</math> | ||
* '''Example 4:''' | * '''Example 4:''' | ||
- | * <math>P(X=5)=0.7^4 0.3=0.07203, where X represents the number of trials. | + | * <math>P(X=5)=0.7^4 0.3=0.07203,</math>where X represents the number of trials. |
* '''Example 5:''' | * '''Example 5:''' | ||
<math> E(X)=\frac{1}{0.30}=3.33</math> | <math> E(X)=\frac{1}{0.30}=3.33</math> |
Revision as of 19:58, 24 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 probability 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:
- ,
Below you can see a SOCR snapshot for this example:
- 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:
- P(X = 5) = 0.505 = 0.03125
- Example 3:
- a. ,
- b.
- Example 4:
- P(X = 5) = 0.740.3 = 0.07203,where X represents the number of trials.
- Example 5:
- Example 6:
- a. ,
- b. P(X = 0) = 1 − 0.999 = .001
0.001 = 0.1n n = 3