Question

Question 3

Suppose that X is a binomial random variable with n= 10 andp = 0.28 . Find P( 3 ).

Write only a number as your answer. Round to 4 decimal places (for example 0.1849). Do not write as a percentage.

Question 4

The probability that a student uses the Academic Resource Center on a regular basis is 0.44 .In a group of 18 students, what is the probability that exactly 4 of them use the Academic Resource Center on a regular basis?

Write only a number as your answer. Round to 4 decimal places (for example 0.2416). Do not write as a percentage.

Question 5

The probability that a randomly selected individual in a certain community has made an online purchase is 0.34 .Suppose that a sample of 12 people from the community is selected, what is the probability that at most 3 of them has made an online purchase?

Write only a number as your answer. Round to 2 decimal places (for example 0.24). Do not write as a percentage.

Answer 1

Question 3

Here, we have :

n = 10

p = 0.28

We use Excel function "BINOM.DIST()" as :

BINOM.DIST(x , n , p , True =Cumulative | False = Probability mass function)

We need to find P(X=3)

P(X=3) = BINOM.DIST(3 , 10 , 0.28 , False ) = 0.2642

Question 4

Here, we have :

n = 18

p = 0.44

Required probability = Probability that exactly 4 of them use the Academic Resource Center on a regular basis = P(X=4)

We use Excel function "BINOM.DIST()" as :

P(X=4) = BINOM.DIST(4 , 18 , 0.44 , False ) = 0.0342

Question 5

Here, we have :

n = 12

p = 0.34

Required probability = Probability that at most 3 of them has made an online purchase = P(X 3)

P(X 3) = BINOM.DIST(3 , 12 , 0.34 , True ) = 0.37