Probability Test

1. A factory that makes bottles knows that, on average, 2.6% of its bottles are defective. What is the probability that in a randomly selected sample of 30 bottles, at least two bottles are defective?

• 0.958

• 0.042

• 0.817

• 0.183

2. A biased die with four faces is used in a game. A player pays 10 counters to roll the die and receives a number of counters equal to the value shown on the die. The table below shows the different values on the die and the probability of each occurring. Find the value represented by N given that the player has an expected loss of three counters each time he plays the game

• 35

• 10

• -35

• -50

When a boy bats at baseball, the probability that he hits the ball is 0.6. In a practice session he gets pitched 20 balls; Let X denote the total number of balls he hits. Assume that his attempts are independent of each other.

3. What is the expected value?

• 33

• 12

• 8

• 26

When a boy bats at baseball, the probability that he hits the ball is 0.6. In a practice session he gets pitched 20 balls; Let X denote the total number of balls he hits. Assume that his attempts are independent of each other.

4.Find P(X $\le$ Var(X))

• 0

• .003

• .998

• .5

When Robin shoots an arrow at a target, the probability that she hits the target is 0.2. In a competition, she has ten attempts to hit the target. If she gets at least two hits on target, she will qualify for the next round.

5. What is the probability that she hits the target exactly 3 times?

• .799

• .201

• 0

• .302

When Robin shoots an arrow at a target, the probability that she hits the target is 0.2. In a competition, she has ten attempts to hit the target. If she gets at least two hits on target, she will qualify for the next round.

6.What is the probability that she fails to qualify for the next round?

• .678

• .322

• .376

• .624

A company producing light bulbs knows that the probability of a new light bulb being defective is 1%

7. What is the probability that a pack of four light bulbs contains at least one defective light bulb?

• .039

• .961

• .001

• .999

A company producing light bulbs knows that the probability of a new light bulb being defective is 1%

8. Mario buys 50 packs of 4 light bulbs. What is the probability that more than five of the packs contain at least one defective light bulb?

• .987

• .013

• .955

• .045

When a weighted die is rolled, the probability of rolling a 4 or a 6 is 3/4, but the other sides are equally likely of being rolled.

9. What is the probability of rolling a 2?

• 3/4

• 1/16

• 1/4

• 3/16

When a weighted die is rolled, the probability of rolling a 4 or a 6 is 3/4, but the other sides are equally likely of being rolled.

What is the probability of rolling a 2 and then a 3?

• 3/4

• 1/64

• 9/16

• 1/256