+0

# help

-1
138
3

Question Help

Suppose a fair die numbered 1 to

7

is rolled

4

times. Complete parts​ (a) and​ (b) below.​(a) Find the probability distribution for the number of times

7

is rolled.

Apr 19, 2019

#1
0

If it is a fair die  7 should be rolled 1 time out of 7   or 1/7 of the time    1/7 x 4 rolls =  4/ 7

Apr 19, 2019
#2
+1

Times a 7 is rolled         Prob

0                           ( 6/7)^4  ≈    .54

1                          C(4,1) (6/7)^3 (1/7)  ≈ .36

2                          C(4,2) (6/7)^2(1/7)^2  ≈  .09

3                          C(4,3) (6/7)(1/7)^3  ≈ .001

4                           (1/7)^4  ≈   0   Apr 19, 2019
edited by CPhill  Apr 19, 2019
#3
-2

The probabilility of a dice 1-7 rolling on a 7 four times is very low. Here's how:

The expression 1/7*1/7*1/7*1/7 or (1/7)^4 is to be evaluated to find the answer.

That is, 1/49*1/49 which equals 1/2401 which equals approximately ~.0004.

The probability is approximately ~0.04%.

~~Hypotenuisance

Apr 21, 2019