Which of the following is the formula for the covariance of X and Y?
a.
b.
c.
d.
Q. 2
Which two measures do an analysis of linear dependency use?
a.The mean and median
b.The mean and cumulative distribution function
c.The covariance and coefficient of linear correlation
d.The mean and standard deviation
Q. 3
Which of the following statements regarding the correlation is not true?
a.
does not imply independence.
b.For any two random variables,
X and
Y,
c.The correlation coefficient is equal to the covariance.
d.
or 
if there is s perfect linear prediction in the population.
Q. 4
Which of the following will equal zero if two random variables, say X and Y, are independent?
a.Covariance
b.Correlation
c.Correlation and Covariance.
d.Variance
Q. 5
What should the value for the covariance between two random variables be if the variables are not strongly related?
a.near zero
b.Negative
c.Positive
d.near one
Q. 6
Which of the following is the correct formula for the standard deviation of a discrete random variable X?
a.
b.
c.
d.
Q. 7 The probability density function for the number of red marbles in a randomly selected sample of colored marbles is given below. What is the probability that there are 3 or fewer marbles in the sample chosen?
a.1.00
b.0.55
c.0.05
d.0
Q. 8
What does P(X = k) equal to for a discrete random variable?
a.
P(
X =
k) = sum of the probabilities of all simple events for which
X =
k b.
P(
X =
k) =
k c.
P(
X =
k) = product of the probabilities of all simple events for which
X =
k d.P(X = k) = 
status: not answered ()
Quick Reply
