Question

A die is tossed thrice. A success is ’getting 1 or 6’ on toss. Find the mean and the variance of the

number of successes.
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Answer 1

Answer:

Step-by-step explanation:

We can use binomial distribution in this case.

N = 3 = No. of throws

X = Getting 1 or 6 on a die

p = Probability of success = 2/6 = 1/3

1-p =Probability of failure = 2/3

Mean = n*p = 3 * 1/3 = 1

Answer 2

Answer:

Step-by-step explanation:

Probability of success is 1/6 + 1/6 = 2/6 = 1/3

Probability of failure is 1 - 1/3 = 2/3

As we know mean = n*p

3*1/3=1

and variance is npq = 3*1/3*2/3 =2/3

so mean is 1 and variance is 2/3

If question asked to find standard deviation than we simply take square rooot of variance = (2/3)^1/2