Econ 120A MT1 Practice
D
If two events are independent, then .. A. they must be mutually exclusive B. the sum of their probabilities must be equal to one C. their intersection must be zero D. none of these are correct
D
Consider the following statements: I) If events A and B have nonzero probabilities, then they can both be independent and mutually exclusive II) The union of events A and B is the event that occurs when either A or B occurs but not both A. Only I is true B. Only II is true C. Both are true D. Both are false
B
Consider the following statements: I. The distance between the 25th percentile and the median is always the same as the distance between the median and the 75th percentile II. The standard deviation is expressed in terms of the original units of measurement but the variance is not. A. Only I is true B. Only II is true C. Both are true D. Both are false
C
Consider the following: I) An event must be independent of its complement II) The probability of (A or B) cannot be less than the probability of (A and B) A. Both are true B. Only I is true C. Only II is true D. Both are false
C
Consider two events A and B. Which is true? A. If the probability of A given B is 0.4, then the probability of A given the complement of B is 0.6 B. If the probability of A given B is 0.4, then the probability of the complement of A given the complement of B is 0.6 C. If the probability of A given B is 0.4, then the probability of the complement of A given B is 0.6. D. If the probability of A given B is 0.4, and the probability of A is 0.4, then events A and B are mutually exclusive.
C
Consider: I) If A and B are independent, then not A and not B must be independent II) An event and its complement are mutually exclusive A. Only I is true B. Only II is true C. Both are true D. Both are false
A
Consider: I) The mean is affected by extreme values, but median is not II) The value of the standard deviation may be either positive or negative, while the value of the variance will always be positive. A. Only I is true B. Only II is true C. Both are true D. Both are false
A
Events A and B are mutually exclusive. If Pr(A) = 0.6, then the probability of B .... A. cannot be larger than 0.4 B. can be any value greater than 0.6 C. can be any value between 0 and 1 D. cannot be determined with the given information
A
In a histogram, the proportion of the total area which must be to the left of the median is: A. exactly 0.50 B. less than 0.50 if the distribution is negatively skewed C. more than 0.50 if the distribution is positively skewed. D. unknown
D
Using an observed sample to make a statement about the unknown population is engaging in _________ reasoning, while going from a known population to the unknown sample is the basis of ___________ reasoning. The former is the realm of statistics while the latter is the sphere of probability theory. A. deductive; inductive B. probabilistic; statistical inference C. deductive; probabilistic D. inductive; deductive
B
Which of the following is not a measure of dispersion? A. the range B. 50th percentile C. standard deviation D. IQR
C
Which of the following statements about the mean is not always correct? A. The sum of the deviations from the mean is zero B. The mean is a measure of the central location C. Half of the observations are on either side of the mean D. The value of the mean times the number of observations equals the sum of all observations
A
Which of the following statements is always true for any two events A and B defined on sample space S? A. If the complement of event A is the empty set, then event A is the sample space S. B. If the union of events A and B is not the empty set ( ), then A n B = ( ) C. If the events A and B are mutually exclusive, then A u B = S D. If the union of events A and B is in the sample space S, then A n B = ( )