Stats Exam 2

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The flashcards below were created by user tenorsextets on FreezingBlue Flashcards.

1. AND=
OR=
• Multiply, independent events?
2. Fundamental Counting Rule
In a sequence of events (like choosing what piece of clothes to wear), multiply the numbers together to get the total number of combinations possible.
3. Permutations
Key words
• When order matters!
• "arrange, order, rearrange, rank, sequence, in how many ways can things be ordered"
4. Permutation formulas
number of permutations of n objects: n! (arrange)

• nPr= n!÷(n-r)! (selected piece and arrange them)
• n= # of objects (bigger #)
• r= selected # (smaller #)
5. Combinations
Key Words
• Order doesn't matter!
• "choose, select, team, committee"
6. Combinations formula
• nCr= n!÷(n-r)!r!
• n= # of objects (bigger #)
• r= selected # (smaller #)
7. Pascals's triangle
• 1
• 1 1
• 1 2 1
• 1 3 3 1
• 1 4 6 4 1
• 1 5 10 10 5 1
8. Probability of 0
Probability of 1
• 0= event never occurs
• 1= event always occurs
9. Drawing a sample space
-tossing a coin
-tossing 2 coins
-rolling a die
• -HH TT HT TH
• -1 2 3 4 5 6
10. Classical probability formula
Prob.= (# of successful outcomes)÷(# of total outcomes)
11. The Compliment
• opposite of event
• 1-fraction probability= compliment
12. Mutually Exclusive
2 events that can't occur at the same time, only use the word OR with this condition
13. When things are not mutually exclusive
add two conditions and subtract overlap

• Example:
• P(king) + P(club) - P(king of clubs)
• 4/52 + 13/52 - 1/52
14. Independent Events
if event A doesn't affects the probability of event B

P(A AND B)= P(A) • P(B)
15. When events are not independent
Don't forget to reduce the denominator by one for each next fraction because you wouldn't be returning "the marbles to the bag"
16. When doing a tough word problem
REWRITE THE QUESTION. Find out what you need and write out what you're finding the probability for.

Example: P(1st yes AND 2nd yes AND 3rd yes)
17. Conditional Probability
conditional statement using the words "if" or "given that"
18. Conditional Probability formula
P(B given A)= P(A and B) ÷ P(A)

Card Set Information

 Author: tenorsextets ID: 76299 Filename: Stats Exam 2 Updated: 2011-03-30 23:55:19 Tags: statistics stats exam probability Folders: Description: read title Show Answers:

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