Pstat 5A midterm 1 UPDATED ACTUAL Exam Questions and CORRECT Answers

Pstat 5A midterm 1 UPDATED ACTUAL
Exam Questions and CORRECT Answers
random experiment - CORRECT ANSWER - an experiment in which we know all of the
possible outcomes
ex.: flipping a coin, flipping a coin twice, rolling a six sided die, rolling 6 six sided die then
flipping a coin


sample space (s) - CORRECT ANSWER - the set of all possible outcomes
ex. flipping a coin
s= {H, T}
ex. flipping a coin twice
s= {HH, HT,TH, TT}
ex. rolling a 6 sided die
s = {1,2,3,4,5,6}
ex. rolling 6 sided die, flipping a coin
s= {1H, 1T, 2H, 2T, 3H, 3T, 4H, 4T, 5H, 5T, 6H, 6T}


Can make a tree diagram or table


tree diagram - CORRECT ANSWER - Can make a tree diagram to find sample space: ex.
flipping a coin 3 times 2^3 = 8 possible outcomes
draw tree diagram:
HT
/\/\
HTHT
/\ /\ /\ /\
H T H T H T HT
s = {HHH, HHT, HTH, HTT, THH, THT, TTH, TTT}

, start from top and go down each of the branches


table - CORRECT ANSWER - can use to find sample space
ex. rolling a 6 sided die twice
123456
1 (1,1) (1, 2) (1, 3) (1, 4) (1,5) (1,6)
2 (2,1) (2,2) (2,3) (2,4) (2,5) (2,6)
3 (3,1) (3,2) (3,3) (3,4) (3,5) (3,6)
4 (4,1) (4,2) (4,3) (4,4) (4, 5) (4,6)
5 (5,1) (5,2) (5,3) (5,4) (5, 5) (5,6)
6 (6,1) (6,2) (6,3) (6,4) (6, 5) (6,6)


s= {1,1) (1, 2) (1, 3) (1, 4) (1,5) (1,6), (2,1) (2,2) (2,3) (2,4) (2,5) (2,6).... (6,1) (6,2) (6,3) (6,4)
(6, 5) (6,6)}


event - CORRECT ANSWER - a group of outcomes within your sample space
- a subset of the sample space
- they are denoted by upper case letters (ie A, B, C)
- exs: rolling a fair 6 sided die
- event A= observe a 4 {4}
- event B= observe an even # {2, 4, 6}
- event C = observe # greater than 4 {5, 6}
- we wish to find the probability of various events


probability - CORRECT ANSWER - the likelihood that a given event will occur
classical definition of it:
- if the # of outcomes is finite and they are all equally likely to occur then:
P(A) = (# of favorable outcomes) / (# of possible outcomes)