In: Statistics and Probability
Suppose you roll, two 6-sided dice (refer back to the sample space in the sample space notes). Write any probability as a decimal to three place values and the odds using a colon. Determine the following:
a. the probability that you roll a sum of seven (7) is .
b. The odds for rolling a sum of four (4) is .
c. The odds against the numbers on both dice being the same is .
When two 6-sided dice are rolled: Total number of outcomes = 6 x 6 =36
a.
Probability that you roll a sum of seven (7)
= Number of ocutomes that favor a sum of seven / Total number of outcomes
Outcomes that favor a sum of seven : (1,6),(2,5),(3,4),(4,3),(5,2),(6,1)
Number of Outcomes that favor a sum of seven = 6
Probability that you roll a sum of seven (7)
= Number of ocutomes that favor a sum of seven / Total number of outcomes = 6/36 = 1/6 = 0.167
Probability that you roll a sum of seven (7) is 0.167
b .
The odds of rolling a sum of four (4)
= Number of outcomes that favor a sum of four (4) : Number of outcomes that do not favor a sum of (4)
Outcomes that favor a sum of four (4) : (1,3),(2,2),(3,1)
Number of outcomes that favor a sum of four(4) = 3
Number of outcomes that do not favor a sum of (4)
= Total number of outcomes - Number of outcomes that favor a sum of four(4) = 36-3 =33
The ods of rolling a sum of four is
Number of outcomes that favor a sum of four(4) : Number of outcomes that do not favor a sum of (4) = 3 : 33
The odds of rolling a sum of four (4) is 3 : 33 or 1:11
c. The odds against the numbers on both dice being the same is .
Outcomes that favor numbers on both dice being the same = (1,1),(2,2),(3,3),(4,4),(5,5),(6,6)
Number of outcomes that favor numbers on both dice being the same = 6
Number of outcomes that do not favor numbers on both dice being the same
=Total number of outcomes - Number of outcomes that favor numbers on both dice being the same
=36-6=30
The odds against the numbers on both dice being the same is .
Number of outcomes that do not favor numbers on both dice being the same : Number of outcomes that favor numbers on both dice being the same
: 30:6 ; 5:1
The odds against the numbers on both dice being the same is . 30:6 or 5:1