AP Statistics Probability Rules

In an AP Statistics class, 50% of students eat breakfast in the morning, 40% of them floss their teeth, and 25% of the students do both.  What is the probability that a randomly chosen student eats breakfast but does not floss their teeth?

• 90%

• 25%

• 75%

• 65%

In an AP Statistics class, 50% of students eat breakfast in the morning, 40% of them floss their teeth, and 25% of the students do both.  What is the probability that a randomly chosen student eats breakfast or flosses their teeth?

• 65%

• 90%

• 25%

• 15%

Four juniors and six seniors have applied for two open student council positions, and administrators have decided to pick two new members randomly.  What is the probability that they are both from the same grade?

• .5556

• .4667

• .52

• .4444

A fair coin has come up "heads" 100 times in a row.  The probability that the coin will come up heads on the next flip is:

• greater than 50%, it's due to happen.
• 50%
• less than 50%, since tails is happening so much.
• Can't be determined

A bicycle shop equips 60% of its bikes with a water bottle holder, and 55% of its bikes are equipped with a kick stand.  34% of the bikes have both features.  What is the probability that a randomly chosen bike has a kick stand GIVEN THAT it has a water bottle holder?

• 34%
• 56.7%
• 61.8%
• 81%

The probability of a tourist visiting an area cave is .7, and of a tourist visiting a nearby park is .6. The probability of visiting both places on the same day is .4. The probability that a tourist visits at least one of these two places is:

• .08

• .28

• .42

• .9

100 people were surveyed. 54 were female, and 46 were male. 33 of the females said they were democrats, and 30 of the males said they were republicans. If a person is randomly selected, what is the probability that they are a democrat?

• 49%

• 46%

• 54%

• 51%

100 people were surveyed.  54 were female, and 46 were male.  33 of the females said they were democrats, and 30 of the males said they were republicans.  If a person is randomly selected, what is the probability that its a democrat  GIVEN THAT it is a female?

• .67
• .49
• .61
• .33

100 people were surveyed.  54 were female, and 46 were male.  33 of the females said they were democrats, and 30 of the males said they were republicans.  If two people are randomly selected, what is the probability they are both males?

• .30
• .46
• .25
• .21

100 people were surveyed.  54 were female, and 46 were male.  33 of the females said they were democrats, and 30 of the males said they were republicans.  If a person is randomly selected, what is the probability a male is chosen GIVEN THAT its a republican?

• .59
• .65
• .35
• .41