Chapter 17 practice Quiz- AP Statistics

To find the mean of a binomial random variable

• Multiply the probability of success times the probability of failure.
• Multiply the number of trials times the probability of failure
• Multiply the number of trials times the probability of success.
• Multiply the number of trials times the probability of success times the probability of failure.

Suppose that a town is randomly selected from the state. Which of these pairs of random variables are most likely independent

• X= Average house size in acres and Y= Average weight of people living in that town
• X= Average house size in acres and Y= Average annual income
• X= Average height of people living in that town and Y= Average weight of people living in that town
• X= Average monthly mortgage payment and Y= Average annual income

What doe this formula calculate: x1p1+x2p2+x3p3+...=Σxipi

• Standard deviation
• Mean
• Expected Value
• Both b and c

What does the ‘S’ in BINS stand for

• Standard Deviation
• Successes
• Set number of trials
• Standard error

Is this a binomial setting? : Shuffle a deck of cards, turn over the first 7 cards, one at a time. Let Z= the number of Kings you observe

• Yes, it successfully satisfies BINS
• No, because there are no binary outcomes
• No, because the probability of success is not the same for each trial
• No, because there are no set number of trials

Is this a binomial setting?: Shuffle a deck of cards. Turn over the top card. Put the card back in the deck and shuffle again. Repeat until you get a queen. Let L=The number of trials until you get a queen

• No, there are no binary outcomes
• Yes, it successfully satisfies BINS
• No, the trials are not independent
• No, there are no set number of trials

Is this a geometric setting?: Shake a bag of 30 marbles, with 10 red marbles, 10 blue marbles, and 10 green marbles. Reach into the bag and pull out a marble. Put the marble back in the bag and shake again. Repeat until you get a green marble. Let G=The number of trials until you get a green marble

• No, there is a set number of trials
• Yes, this successfully satisfies BITS
• No, the trials are not independent
• No, there are no binary outcomes

You are to take a multiple choice exam consisting of 100 questions with five possible responses to each. Suppose you have not studied and decide to guess randomly on each question. Let X=# correct responses on the exam. What is your expected score on the exam?

• 20
• 25
• 40
• 80

Suppose 5% of cereal boxes contain a prize. You are determined to buy cereal boxes until you win a prize. What is the probability you will have to buy exactly 4 boxes?

• .032
• .9571
• .2635
• .0429

Sally read that ⅙ eggs contains salmonella, so she only uses 10 eggs out of a dozen. If eggs do or don’t contain salmonella independently of each other, the number of contaminated eggs in a carton when Sally chooses 10 at random has the following distribution (based on chapter 6.3 review)

• Binomial; n=12 and p=1/6
• Binomial; n=10 and p=⅙
• Geometric; n=12 and p= 1/6
• Geometric; n=10 and p= ⅙