What is the mean of the wholesaler's monthly sales?
A) 326,400
B) 135,620
C) 132,840
D) 163,200
Q. 2For two independent random variables X and Y, which of the following identities is always true?
A) E(2X + 3Y) = E(X) + E(Y) + 5
B) Var(2X + 3Y) =2Var(X) + 3Var(Y)
C) Var(2X + 3Y) = 4Var(X) + 9Var(Y)
D) E(2X + 3Y) = 5E(X+Y)
Q. 3The interquartile range is the average of the first and third quartiles.
Indicate whether the statement is true or false
Q. 4Discuss briefly the difference between descriptive and inferential statistics.
What will be an ideal response?
Q. 5If a sample of size 120 is selected, the value of A for the probability P(-A t
A) = 0.98 is:
A) 1.960
B) 2.576
C) 1.282
D) 2.326
Q. 6The median score for the final exam in a statistics class was 85 and 20 percent of the students received a grade greater than 90. What is the probability that a randomly selected exam had a score between 85 and 90?
A) 80 percent
B) 30 percent
C) 50 percent
D) There is not sufficient information to answer this question.