Question

PLEASE HELP a dice is rolled 8 times. find the probability. p(getting at least 7 even numbers)
a. 1/256
b. 9/256
c. 1/32
d. 1/16

Answer 1

any ideas?

Answer 2

total number of permutations when a dice is rolled 8 times = 6^8

Answer 3

\[3/48\]= x

Answer 4

even numbers : 2, 4, 6

so, out of 8 times u perform experiment, 7 times - u have 3 choices : 3^7
one time you have 6 choices : 6

total permutations in favor = 3^7 * 6

Answer 5

how did you get 3/48??

Answer 6

At least 7 even is the same as at most 1 odd.
0 odd = 1/256
1 odd = 8/256
Total = 9/256

Answer 7

p(getting at least 7 even numbers) = \(\frac{3^7*6}{6^8}\)

= \(\frac{3^7}{6^7}\)

= \(\frac{3^7}{3^7.2^7}\)

=\(\frac{1}{2^7}\)

=\(\frac{1}{256}\)

Answer 8

there are 3 even numbers on a dice and 3 odd and you dividethe 3 even by 8 times and that will give you the answer

Answer 9

6times 8 is 48 and divide by 3 and you will get 16 so the answer is 1/16

Answer 10

okay...so what if you were looking for 8 odd numbers? wouldn't it be the same process?

Answer 11

yes

Answer 12

well i got the same answer..1/16...is that right?

Answer 13

yes

Answer 14

Binomial distribution:
P(n,i)=(n,i)p^i q^(n-i)
(n,i)=n!/(i!(n-i)!)
Here, p=q=1/2
(8,0)=1
(8,1)=8
(8,2)=8*9/2=36, ...
So any number of even or odd can be calculated.

Answer 15

You have to have 7 throws even and the 8th one can be either.
\[
\frac 1{2^7} 8=\frac 1 {16}
\]

Answer 16

You multiply by 8 to count where the even or odd throw is.

Answer 17

yes

Answer 18

thanks:)

Answer 19

your welcome