 | Chapter 6 True/False Quiz | | Chapter 7 Summary |
| Chapter 8 True/False Quiz | | Return to Quiz Index | | Return to Main Page |
Statistics
|
| Chapter 6 True/False Quiz | | Chapter 7 Summary |
| Chapter 8 True/False Quiz | | Return to Quiz Index | | Return to Main Page |
1. A random variable can assign a different number to each possible outcome.
True 
False
2. A random variable must assign a different number to each possible outcome. True False
3. The sum of all the probabilities P(X=x) for all possible values of x must equal 1. True False
4. The histogram of X will be highest at the expected value of X. True False
5. The expected value of X is half-way between the largest and smallest possible values of X. True False
6. If m is the median of X, then it must be the case that P(X 
m) = 1/2 and P(X 
m) = 1/2. True False
7. If E(X) is the expected value of X, then E(X
E(X)) = 0. True False
8. If E(X) is the expected value of X, and x1, x2, . . ., xn are X-scores obtained in an experiment, then (x1 + x2 + . . . + xn) / n = E(X). True False
9. If E(X) is the expected value of X, and x1, x2, . . ., xn are X-scores obtained in an experiment, then (x1 + x2 + . . . + xn)/n should be close to E(X) if n is large. True False
10. In a sequence of n independent Bernoulli trials, with a probability p of success in each, we expect to get about np successes. True False
11. We should expect the actual values of X obtained in experiments to be one standard deviation away from the mean. True False
12. If E(X) is the expected value of X, we should expect the average of |XE(X)| to be one standard deviation. True False
13. If E(X) is the expected value of X and s(X) is the standard deviation, we should expect the average of (XE(X))2 to be s(X)2. True False
14. For any X, the majority of its values obtained in experiments will lie within one standard deviation of its mean. True False
15. For a normal X, the majority of its values obtained in experiments will lie within one standard deviation of its mean. True False
16. For any X, at least 3/4 of its values obtained in experiments will lie within 2 standard deviations of its mean. True False
17. For a normal X, at least 95% of its values obtained in experiments will lie within 2 standard deviations of its mean. True False
18. For any X, at least 88% of its values obtained in experiments will lie within 3 standard deviations of its mean. True False
19. For a normal X, at least 99% of its values obtained in experiments will lie within 3 standard deviations of its mean. True False
20. A binomial distribution has exactly the same probabilities as a normal distribution. True False