AP Stats Chapter 5

What is the probability that a student has a GPA under 2.0 given that he or she has skipped many classes?

• 0.080

• 0.281

• 0.285

• 0.314

• 0.727

Dr. Stats plans to toss a fair coin 10,000 times in the hope that it will lead him to a deeper understanding of the laws of probability. Which of the following statements is true?

• It is unlikely that Dr. Stats will get more than 5000 heads.

• Whenever Dr. Stats gets a string of 15 tails in a row, it becomes more likely that the next toss will be a head.

• The fraction of tosses resulting in heads should be exactly 1/2.

• The chance that the 100th toss will be a head de pends somewhat on the results of the first 99 tosses.

• It is likely that Dr. Stats will get about 50% heads.

China has 1.2 billion people. Marketers want to know which international brands they have heard of. A large study showed that 62% of all Chinese adults have heard of Coca-Cola. You want to simulate choosing a Chinese at random and asking if he or she has heard of Coca-Cola. One correct way to assign random digits to simulate the answer is:

• One digit simulates one person’s answer; odd means “Yes” and even means “No.”

• One digit simulates one person’s answer; 0 to 6 mean “Yes” and 7 to 9 mean “No. ”

• One digit simulates the result; 0 to 9 tells how many in the sample said “Yes.”

• Two digits simulate one person’s answer; 00 to 61 mean “Yes” and 62 to 99 mean “No. ”

• Two digits simulate one person’s answer; 00 to 62 mean “Yes” and 63 to 99 mean “No. ”

Choose an American household at random and record the number of vehicles they own. Here is the probability model if we ignore the few households that own more than 5 cars. A housing company builds houses with two-car garages. What percent of households have more cars than the garage can hold?

• 7%

• 13%

• 20%

• 45%

• 55%

What is the probability that a student has a GPA under 2.0?

• 0.227

• 0.255

• 0.450

• 0.475

• 0.506

For events A and B related to the same chance process, which of the following statements is true?

• If A and B are mutually exclusive, then they must be independent.

• If A and B are independent, then they must be mutu ally exclusive.

• If A and B are not mutually exclusive, then they must be independent.

• If A and B are not independent, then they must be mutually exclusive.

• If A and B are independent, then they cannot be mutually exclusive.

A deck of playing cards has 52 cards, of which 12 are face cards. If you shuffle the deck well and turn over the top 3 cards, one after the other, what’s the probability that all 3 are face cards?

• 0.001

• 0.005

• 0.010

• 0.012

• 0.02

I toss a penny and observe whether it lands heads up or tails up. Suppose the penny is fair, that is, the probability of heads is 1/2 and the probability of tails is 1/2. This means...

• that every occurrence of a head must be balanced by a tail in one of the next two or three tosses

• that if I flip the coin many, many times, the proportion of heads will be approximately 1/2 and this proportion will get closer and closer to 1/2 as the number of tosses increases.

• that regardless of the number of flips, half will be heads and half will be tails

• generally, the flips will alternate between heads and tails

• all of the above

A phenomenon is observed many, many times under identical conditions. The proportion of times a particular event A occurs is recorded. The proportion represents

• the probability of the event A.

• the distribution of the event A.

• the correlation of the event A.

• the proportionality of the event A.

• the variance of event A.

Suppose we have a loaded die that gives the outcomes 1-6 according to the following probability distribution. Note that for this die all outcomes are not equally likely, as they would be if the die were fair. If this die is rolled 6000 times, the number of times we get a 2 or 3 should be about

• 1000

• 2000

• 3000

• 4000

• The answer cannot be determined since the probabilities are only approximate.