I. Consider the random experiment of rolling a pair of dice.Note: Write ALL probabilities as reduced fractions or whole numbers(no decimals).
1-1 | 2-1 | 3-1 | 4-1 | 5-1 | 6-1 |
1-2 | 2-2 | 3-2 | 4-2 | 5-2 | 6-2 |
1-3 | 2-3 | 3-3 | 4-3 | 5-3 | 6-3 |
1-4 | 2-4 | 3-4 | 4-4 | 5-4 | 6-4 |
1-5 | 2-5 | 3-5 | 4-5 | 5-5 | 6-5 |
1-6 | 2-6 | 3-6 | 4-6 | 5-6 | 6-6 |
2) How many outcomes does the sample space contain?_____36________
3)Draw a circle (or shape) around each of the following events(like you would circle a word in a word search puzzle). Label eachevent in the sample space with the corresponding letter.
A: Roll a sum of 3.
B: Roll a sum of 6.
C: Roll a sum of at least 9.
D: Roll doubles.
E: Roll snake eyes (two 1’s). F: The first die is a 2.
3) Two events are mutually exclusive if they have no outcomes incommon, so they cannot both occur at the same time.
Are C and F mutually exclusive? ___________
Using the sample space method (not a special rule), find theprobability of rolling a sum of at least 9 and rolling a 2 on thefirst die on the same roll. P(C and F) = __________
Using the sample space method (not a special rule), find theprobability of rolling a sum of at least 9 or rolling a 2 on thefirst die on the same roll.
P(C or F) = __________
4) Special case of Addition Rule: If A and B are mutuallyexclusive events, then
P(A or B) = P(A) + P(B)
Use this rule and your answers from page 1 to verify your lastanswer in #6:
P(C or F) = P(C) + P(F) = ________ + ________ = _________
5) Are D and F mutually exclusive? __________
Using the sample space method, P(D or F) = _________
6) Using the sample space method, find the probability ofrolling doubles and rolling a “2†on the first die.
P (D and F) = _______
7) General case of Addition Rule: P(A or B) = P(A) + P(B) – P(Aand B)
Use this rule and your answers from page 1 and #9 to verify yourlast answer in #8:
P(D or F) = P(D) + P(F) – P(D and F) = ________ + ________ −________ = _________
8) Two events are independent if the occurrence of one does notinfluence the probability of the other occurring. In other words, Aand B are independent if P(A|B) = P(A) or if P(B|A) = P(B).
Compare P(D|C) to P(D), using your answers from page 1: P(D|C) =________ P(D) = ________ Are D and C independent? _________ because_______________________________
When a gambler rolls at least 9, is she more or less likely toroll doubles than usual? ___________ Compare P(D|F) to P(D), usingyour answers from page 1: P(D|F) = ________ P(D) = ________
Are D and F independent? __________ because______________________________
9) Special case of Multiplication Rule: If A and B areindependent, then P(A and B) = P(A) · P(B).
Use this rule and your answers from page 1 to verify your answerto #9: P(D and F) = P(D) • P(F) = ________ · ________ = ________.
10) Find the probability of rolling a sum of at least 9 andgetting doubles, using the sample space method.
P(C and D) = ___________ .
11) General case of Multiplication Rule: P(A and B) = P(A) ·P(B|A).
Use this rule and your answers from page 1 to verify your answerto #13: P(C and D) = P(C) • P(D|C) = ________ · ________ = ________.