Assuming a binomial distribution, what is the probability that at least 4 of the next 10 customers will purchase popcorn?

Question

The Boy Scouts of America organization has determined that 20% of supermarket customers will purchase popcorn outside the store from cub scouts for its yearly fundraising efforts.

Assuming a binomial distribution, what is the probability that at least 4 of the next 10 customers will purchase popcorn?

 

Need the excel formula and how you got to it. Thanks

Answer 1

The probability that at least 4 of the next 10 customers will purchase popcorn

= 1 - The probability that at most 3 of the next 10 customers will purchase popcorn

= 1 − BINOMDIST(3, 10, 0.20, TRUE)

= 1 − 0.879126

= 0.120874

 

Note on the EXCEL function

 

To find the probability of exactly k success in n trials, use
BINOMDIST(k, n, p, FALSE)

To find the probability of up to k success in n trials, use
BINOMDIST(k, n, p, TRUE)