Geometric or Binomial

counts the number of successes in a fix number of trails. X = 0,1,2,3,…,n

• Geometric

• Binomial

• Both

• Neither

counts the number of trials needed to obtain the 1st success. X = 1,2,3,…

• Geometric

• Binomial

• Both

• Neither

Each observation falls into one of two categories: “success” or “failure”

• Geometric

• Binomial

• Both

• Neither

The n observations are all independent.

• Geometric

• Binomial

• Both

• Neither

The probability of success, p, is the same for each observation.

• Geometric

• Binomial

• Both

• Neither

The variable of interest is the number of trials required to obtain the first success

• Geometric

• Binomial

• Both

• Neither

A restaurant offers a game piece with each meal to win coupons for free food. The probability of a game piece winning is 1out of 4 and is independent of other game pieces winning. A family orders 4 meals. Let C be the number of coupons the family wins.

What type of variable is C?

• Geometric

• Binomial

• Both

• Neither

Alma wrote a phone app. She has noticed that 3% of the users who download her app upgrade it the same day. Let N be the number of customers who download Alma's app until one upgrades it on the same day. Assume that the probability of each user's upgrades are independent.

What type of variable is N?

• Geometric

• Binomial

• Both

• Neither

Leo selects 25 grandparents at random from his town to interview. In the town, 35% of the grandparents have their grandchildren living with them. Let G be the number of grandparents Leo interviews whose grandchildren are living with them.

What type of variable is G?

• Geometric

• Binomial

• Both

• Neither

The American Red Cross says that about 11% of the U.S. population has Type B blood. A blood drive is being held at your school. How many blood donors should the American Red Cross expect to collect from until it gets a donor with Type B blood? 

• 9.1 donors
• 8.5 donors
• 10.3 donors
• Cannot be determined.