I love math but probability is not my favorite..... I just never understood it!!
Two standard unbiased dice are thrown.
a) Find the probability that the sum of the scores is 9.
b) " " " " " the scores differ by 1.
c) " " ' " ' the sum of the scores is 9 or that the scores differ by 1.
I don't understand what unbiased means..? Or how to get the answers..!
2006-11-28 13:21:13 · 4 answers · asked by Anonymous in Education & Reference ➔ Homework Help
Hi there!
Disregard the word "unbiased" which just means "non-oblique" or "unloaded" and therefore implies it's a random event (the probabilities of getting any single score from the dice are the same, all 1/6, fair enough).
Since the total number of all configurations is 6^2=36 (cuz each dice has 6 different scores, from 1 to 6), the number 36 will be the denominator for all the following probability calculations.
a) Possible configurations: 3&6, 4&5, 5&4, 6&3 -- so there're 4. Then the probability is 4/36=1/9.
b) Possible configurations: 1&2, 2&3, 3&4, 4&5, 5&6, and vice versa -- so there're 5*2=10. Then the probability is 10/36=5/18.
c) Just unite the configuations from a) & b) and merge the ones they have in common (CAUTION: the conjunction in part c) is "OR" rather than "AND"! It DOES matter!), and the number of possible configurations turns out to be 4+10-2=12 (cuz 4&5 and 5&4 are what they have in common and are supposed to count only once). Then the probability is 12/36=1/3.
Hope these make sense to u..Good Luck!..^^
2006-11-28 13:53:35 · answer #1 · answered by ee 1 · 0⤊ 0⤋
the scores are 4 and 5 because they differ by one. There is only one chance that you could get two scores that add up to 9 and have a difference of 1.
2006-11-28 23:14:39 · answer #2 · answered by gounc1_5 1 · 0⤊ 0⤋
unbiased means that the chance of the dice coming up with any score when u roll it are the same. a dice has 6 sides, so an undiased or fair dice each side has the same probability of coming up when u roll it, ie:1/6. the opposite is a loaded die, or cheat die which is made to come up a certain score. get caught in a casino with a loaded die and u'r in trouble.
as for the answers, sorry, but my math skills suck.
2006-11-28 21:35:20 · answer #3 · answered by implosion13 4 · 0⤊ 0⤋
Neither are "loaded". That is weighted.
-MM
2006-11-28 21:32:27 · answer #4 · answered by Anonymous · 0⤊ 0⤋