Which of the following statements is always true for any two events A and B defined on a sample space S?
A) The complement of event A is event B.
B) The intersection of A and B is the set of all basic outcomes in either A or B.
C) If events A and B are mutually exclusive, then A B = S.
D) If events A and B are collectively exhaustive, then A B = S.
Q. 2The covariance of the following sample data of four (X, Y) pairs: (1, 5 ), (2, 10 ), (4, 7 ), and (5, 9 ) equals:
A) 1.25
B) 2.50
C) 3.75
D) 3.69
Q. 3Anita collected a data set on the weights (to the nearest pounds) of all students at her university. The best graph to describe this data is a:
A) histogram
B) pie chart
C) bar chart
D) scatter plot
Q. 4For any distribution, the percent of observations that lie within four standard deviations of the mean is:
A) 93.75 or more.
B) 93.75 or less.
C) 6.25 or more.
D) 6.25 or less.
Q. 5Which of the following statements about a pie chart is false?
A) A pie chart is graphical representation of the proportion or percentage of frequency of each category of a categorical variable.
B) A pie chart is usually used to display the relative sizes of categories of a numerical variable.
C) A pie chart always has the shape of a circle.
D) The size of each slice of a pie chart is the proportion or percentage of frequency of the corresponding category of a categorical variable.
Q. 6Suppose you roll a pair of dice. Let A be the event that you roll an even number. Let B be the event that you roll an odd number. Which of the following statements is true?
A) The events A and B are not mutually exclusive.
B) The intersection of A and B is the empty set .
C) The events A and B are not collectively exhaustive.
D) The complement of event B is the set 1, 3, 5, 7, 9, 11.