Lecture 5 - Probablity

Question 1

Chance behaviour is unpredicatable in the ____ term, but predictable over the -___ run

Answer 1

short, long

Question 2

Sample space

Answer 2

the set of all possible outcomes

Question 3

Probability model

Answer 3

the description of a chance process which includes the sample space and the probability of each outcome

Question 4

What are the 4 probability rules

Answer 4

1. Any probability is anumber b/w 0 and 1
2. All possible outcomes together must have a probability 1
3. If two events have no outcomes in common, the prob that one or the other occurs is the sum of their individual probabilities
4. The probabilities that na event does no occur is 1 minus the pobability that the event does occure

Question 5

Rule 1

Answer 5

The probability P(A) of any event A satisfies 0<P(A)<1

Question 6

Rule 2

Answer 6

If S is the sample space in a probability model, then P(S)=1

Question 7

Rule 3 - addition rule for disjoints

Answer 7

If A and B are disjoint, P(A orB) = P(A)+P(B)

Question 8

Rule 4

Answer 8

The complement of any event A is the event that A does not occur. P(A^C)=1-P(A)