Introduction to Statistics

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 ½

• The chance that the 100th toss will be a head depends somewhat on the previous 99 tosses.

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

Choose an American household at random and record the number of vehicles they own. Here is the probability model if we ignore the 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%

One thousand students at a city high school were classified according to both GPA and whether or not they consistently skipped classes. The table summarizes the data:

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

• 0.227

• 0.255

• 0.450

• 0.475

• 0.506

One thousand students at a city high school were classified according to both GPA and whether or not they consistently skipped classes. The table summarizes the data:

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

• 0.080

• 0.281

• 0.285

• 0.365

• 0.727

One thousand students at a city high school were classified according to both GPA and whether or not they consistently skipped classes. The table summarizes the data:

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

• 0.365

• 0.727

Choose an American adult at random. The probability that you choose a woman is 0.52. The probability that the person you choose has never been married is 0.25. The probability that you choose a woman who has never been married is 0.11. The probability that person you choose is either a woman or has never been married (or both) is therefore about

• 0.77

• 0.66

• 0.44

• 0.38

• 0.13