# Which Probabilty Formula?

#### Bishop

More than 200 billion grocery coupons are distributed each year for discounts exceeding $84 billion. However, according to a report in USA Today, only 3.2% of the coupons are redeemed. If a company distributes 5000 coupons, what is the probability that: (a) at least 100 coupons are redeemed? Just need to know which formula I should use to solve this problem? #### arquestions ##### New Member approximate using the normal distribution Here, n=5000 p=0.032 You are looking for the probability that more than 100 coupons are redeemed. The appropriate way to solve this problem is using the binomial distribution. However, because n is large we can approximate the binomial distribution with a normal distribution with mean=np and variance=np(1-p). From there you are looking to solve for P(X>100). Hope this helps!! www.analyticalreasoning.com More than 200 billion grocery coupons are distributed each year for discounts exceeding$84 billion. However, according to a report in USA Today, only 3.2% of the coupons are redeemed. If a company distributes 5000 coupons, what is the probability that:

(a) at least 100 coupons are redeemed?

Just need to know which formula I should use to solve this problem?