STch4

CHAPTER 4

Probability - Inferential Statistics

• Principles of probability
  • P(s) = 1 0<p<p(E)<1
  • Ei(n)Ej =/= 0 i=/=j
  • Sum of E1…En = S
  • Sum P(E1)…P(E)n = 1
• Interpretation:
• What does P=1 mean?
• What does P=0 mean?

Prob for one event Prob for two events

• Mutually exclusive/*independence
  • ME P(1n2)
  • I P(A) * P P(B)
  • Mutually exclusive are not empty sets
• Complement
  • P(E^c) = 1-P(E)
• Conditional probability
• Law of Large Numbers
• Prob For One Event
  • P(E)=#E /#outcomes
• Outcomes

Permutations and Combinations:

• Combination - pays no attention to order
  • Permutation over permutation
  • Arrangement of things considered
• Permutation- ordered grouping of objects
  • Simple permutation
  • Selection where order is no importance
• Odds: ratio that is in favor of the event
  • P(a)/P(a')

Factorials

Tree Diagrams and Probability:

Terminology:

• Statistical Experiment/Obeservation
• Event
• Simple event
• Sample event
• Complement
• Independent: if the occurrence or nonoccurence of one does not change the probability that the other will occur
  • Mutually exclusive
• Dependent:
  • Conditional probability