AP Statistics



Name:_________________________ Date:_______________ Period: ____ AP Statistics

Worksheet 8-1, 2

Mixed Binomial and Geometric Practice

1. Indicate whether a binomial, geometric or neither are a reasonable probability model for the random

variable X

• You have a bag with 20 marbles in which fifteen of the marbles are red and the remaining five are white. The experiment consists of drawing marbles (without replacement ) until you have a white. The number X of failures is recorded.

• Susie lives in Smalltown, USA. She is interested in knowing X, how many people, out of the next 20, run the stop light in town. Assume that the probability of running a stop light is .18.

• Sammie is a dog who loves to play catch. Unfortunately, she isn’t very good and only catches a ball one out of every ten tosses. X represents the number of tosses of the ball thrown before Sammie catches the ball.

2. According to a recent Census Bureau report, 12.7% of Americans live below the poverty level.

Suppose you plan to sample at random 100 Americans and count the number of people who live

below the poverty level. What is the probability that you count 10 or fewer?

3. If you roll a pair of dice, what are the chances of getting doubles for the first time on the 5th roll?

4. A potential buyer will sample videotapes from a large lot of new videotapes. If she finds at least one

defective one, she’ll reject the entire lot. If ten percent of the lot is defective, what is the probability

that she’ll find a defective tape by the 4th videotape?

5. “One in 10 high school graduates in the state of Florida sends an application to the University of

Florida,” says the direct of admissions. If Florida has 120,000 high school graduates next year, how

many applicants would they expect?

6. An automatic welding machine is being considered for production. It will produce a successful weld

99% of the time. If a random sample of 10 welds performed by the machine were selected, what is the

probability that from 7 to 9 of the welds are successful?

7. According to a study published by a group of University of Massachusetts sociologist, about two-

thirds of the 20 million persons in this country who take Valium are women. If a random sample of

38 Valium users are taken, what is the probability that 10 of them are women?

8. The Texas Tango scratch-off lottery offers a 1 in 4 chance of winning, including “breakeven” prizes.

Suppose I wish to play until I win. Let X = the number of scratch offs it takes to get the first win.

(a) What is the probability that the winning ticket I buy is the first one?

(b) What is the probability that my first win is on the 4th ticket?

(c) What is the probability that it takes more than 4 tickets to get my first win?

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download