Statistics Week 7

16. If the probability equals .01 that any randomly selected person from the general population has an IQ of 145 or above, what's the probability that three randomly selected people all will have IQs of 145 or above?

.01 x .01 x .01

17. Given that the probability equals .025 that a randomly selected z score (from the standard normal table) deviates above 1.96, the probability that a z score deviates either above 1.96 or below 1.96 equals

.025 + .025

11. Assume that in a statistics class the probability of receiving a grade of A equals .30 and the probability of receiving a grade of B equals .30. The probability that a randomly selected student from this class will receive a grade other than an A or a B equals

.40

8.37 Assume that in a statistics class the probability of receiving a grade of A equals .30 and the probability of receiving a grade of B equals .30. The probability that a randomly selected student from this class will receive a grade other than an A or a B equals

.40

10. Assume that in a statistics class the probability of receiving a grade of A equals .30 and the probability of receiving a grade of B equals .30. The probability that a randomly selected student from this class will receive either an A or a B equals

.60

22. A roulette wheel has 38 slots in which the ball can land. Two of the slots are green, 18 are red, and 18 are black. The ball is equally likely to land in any slot. The roulette wheel is going to be spun twice and the outcomes of the two spins are independentThe probability that it lands on green at least once in the two spins is

0.1053

21. A roulette wheel has 38 slots in which the ball can land. Two of the slots are green, 18 are red, and 18 are black. The ball is equally likely to land in any slot. The roulette wheel is going to be spun twice and the outcomes of the two spins are independent The probability that it lands on red the first time and black the second time is

0.2244

24. In a particular game, a fair die is tossed. If the number of spots showing is a six, you win $6, if the number of spots showing is a five, you win $3, and if the number of spots showing is 4, you win $1. If the number of spots showing is 1, 2, or 3, you win nothing. You are going to play the game twice.T he probability that you win over $10 in total on the two plays of the game is

1/36

13. On the assumption that voters do not prefer either of four candidates, the probability of a vote for one of these candidates, say candidate A, equals

1/4

23. In a particular game, a fair die is tossed. If the number of spots showing is a six, you win $6, if the number of spots showing is a five, you win $3, and if the number of spots showing is 4, you win $1. If the number of spots showing is 1, 2, or 3, you win nothing. You are going to play the game twice.The probability that you win nothing on the two plays of the game is

1/4

12. Consider using the addition rule when simple outcomes are connected by the word

or

8.24 If subjects are being sampled from a real population, then the study is best described as

a survey

5. A sample is random if the selection process generates a set of observations that is

a.representative. b.none of the options are correct c.nonsystematic. d.haphazard.

2. A real population is one in which all observations are

accessible

8.14 Tables of random numbers are created by

computers

8.30 If a long string of coin tosses reveals that heads occur more often than tails for a particular coin, then the probability of heads for that coin is

greater than 1/2

9. If a long string of coin tosses reveals that heads occur more often than tails for a particular coin, then the probability of heads for that coin is

greater than 1/2

4. Subjects in experiments are viewed as samples from populations that are

hypothetical

14. If an outcome has a probability of zero, the occurrence of that outcome is

impossible

25. Suppose we toss a coin and roll a die. Let A be the event that the number of spots showing on the die is three or less and B be the event that the coin comes up heads. The events A and B are

independent

8.33 An entire set of probabilities always sums to

one

1. It would be impossible to survey a population consisting of all

possible tosses of a particular coin

20. To assess the opinion of students at the Griffith University about campus safety, a member of the SRC interviewed 15 students she meets walking on the campus late at night who are willing to give their opinion.The sample obtained is

probably biased

8. Probability refers to the

proportion of times some event will occur.

8.8 Generalizations to hypothetical populations should be viewed as

provisional

7. In experiments, subjects are assigned

randomly

15. If the probability of some outcome is small, that outcome is viewed as

rare

3. Pollsters conduct surveys based on

real populations

8.16 The tables of random numbers should be entered at

some haphazardly determined point

18. To assess the opinion of students at the Griffith University about campus safety, a member of the SRC interviewed 15 students she meets walking on the campus late at night who are willing to give their opinion. The sample is

the 15 students interviewed.

6. When taking a random sample of ten students from a large class that contains about equal numbers of males and females, you obtain nine males and only one female. This particular outcome is

unlikely, but possible

19. To assess the opinion of students at the Griffith University about campus safety, a member of the SRC interviewed 15 students she meets walking on the campus late at night who are willing to give their opinion. The method of sampling used is

voluntary response