Probability Models Quiz 7 (30 MCQs)

Quiz Instructions

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1. Given that families continue to have children until they get a girl, what is the expected number of children per family? Standard deviation?
2. Which of the following is FALSE about binomial probabilities?
3. Find the probability of achieving success with the event:Rolling a die twice in a row and getting two threes.
4. A marksman has 80% accuracy hitting targets at 1, 000 yards. What is the probability that he will make exactly 18 of his next 20 shots?
5. The mean and standard deviation of a population are 400 and 40, respectively. Sample size is 25. What is the mean of the sampling distribution?
6. How is uniform probability used in statistics?
7. A model predicts that a fair coin will land heads up 50% of the time. If you flip the coin 100 times and get 48 heads, is this result consistent with the model?
8. About 12% of children are believed to have nearsightedness. A school tests the vision of 169 kindergarten students. How many do you expect to be nearsighted?
9. Clara picks a card at random, puts it back, and then picks another card at random.
10. A number cube is weighted so that the faces 1, 2, or 3 are all twice as likely to occur as each of the faces labeled 4, 5, or 6. What statements must you add to P(1)=2/9, P(2)=2/9, P(3)=2/9 to make a complete probability model?
11. Which of the following expressions can be used to calculate the probability of two related events occurring?
12. In 2010, an Angus Reid Public Opinion poll found that 56% of all Canadians admit to regularly swearing when they converse with friends (46% for Americans). A researcher plans to select a random sample of 200 Canadians from Montreal to further survey them about this topic. Verify that a Normal model is a useful approximation for the Binomial in this situation.
13. Matilda is spinning a spinner with eight equal-sized sections numbered 1 through 8. She spins the spinner two times. What is the probability that Matilda's first spin will be an odd number and her second spin will be a number less than 3?
14. If you flip a coin three times, what is the probability of getting heads all three times?
15. For college students, 30% are enrolled in math, 55% are enrolled in English, and 14% are enrolled in both. If a student is selected at random, find the probability that the student is enrolled in either mathematics or English, but not both.
16. 60% of the commercials aired on a network from 8 PM to 10 PM are 15 seconds long, 20% are 30 seconds long, and the rest are 60 seconds. What is the standard deviation?
17. Sandra spins the pointer of a spinner. The spinner has four equal sections labeled 1 to 4. What is the probability that the pointer will land on a number less than 5?
18. What is the probability of an event that cannot happen?
19. What is the sum of the probabilities of all possible outcomes of an event?
20. A computer chip manufacturer rejects 2% of the chips produced because they fail presale testing. If you have a random sample of 400 chips, what is the mean number of chips you expect to fail?
21. Suppose you buy a ticket for $ 6 out of a lottery of 1000 tickets where the prize for the one winning is to be $ 800. How much money do you take home (after paying for it)? HINT:set up a probability model.
22. A weather model predicts a 30% chance of rain each day. If it rains for 5 days in a row, should you question the model?
23. Gavin has 7 shirts, 5 pairs of pants, and 3 pairs of shoes. How many possible outcomes of 1 shirt, 1 pair of pants, and 1 pair of shoes are possible?
24. Which is the best way to simulate choosing one student out of 12 to be the class president?
25. A student group sells 500 raffle tickets for $ 2 each. At the drawing the top prize will be a gift certificate for $ 100. Second prize will be a $ 50 gift card and there will be five 3rd prizes, each a $ 20 gift card. What is the expected value of a ticket?
26. Is this a binomial experiment? Shuffle a deck of 52 cards. Turn over the top card. Put the card back in the deck, shuffle again. Repeat the process 50 times. Let X = the number of aces you observe.
27. What part of the venn diagram does $A\cup B$
28. Ghazal is picking out a snack. She has a banana, an orange, an apple, and a pear to choose from. Which answer choice represents the sample space?
29. In a tree diagram, each branch represents:
30. A jar contains 2 green marbles, 4 blue marbles, 3 yellow marbles, and 2 black marbles. A marble is chosen at random from the jar and replaced. Then a second marble is chosen at random. Find the probability of the first marble being green and the second marble being yellow.