981. Var (X) = ?
A. E[X2]
B. E[X2] – E[X]
C. E[X2] + E[X]2
D. E[X2] – E[X]2

982. Var (X + Y) = ?
A. E[X/Y] + E[Y]
B. E[Y/X] + E[X]
C. Var(X) + Var(Y) + 2 Cov(X, Y)
D.Var(X) + Var(Y) – 2 Cov(X, Y)

983. What is variance of the data set: 2, 10, 1, 9, and 3?
A. 15.5
B. 17.5
C. 5.5
D. 7.5

984. In a module, quiz contributes 10%, assignment 30%, and final exam contributes 60% towards the final result. A student obtained 80% marks in quiz, 65% in assignment, and 75% in the final exam. What are average marks?
A. 64.5%
B. 68.5%
C. 72.5%
D. 76.5%

985. What is the average of 3%, 7%, 10%, and 16% ?
A. 8%
B. 9%
C. 10%
D. 11%

986. If an experiment is repeated independently for a large number of times, it converges to a/an
A. expected value
B. variance – mean
C. normal distribution
D. uniform distribution

987. Which statistical method is used to estimate the relationship between two variables?
A. Correlation
B. Regression
C. Covariance
D. ANOVA

988. The value of R2, the coefficient of determination, is always between
A. 0 and 1, including 0 and 1
B. 0 and 1, excluding 0 and 1
C. –1 and 1, including –1 and 1
D. –1 and 1, excluding –1 and 1

989. The mean, mode, and median of the data set: 5, 4, 10, 12, 1, 5, 3, 7, 15, and 8 is respectively
A. 5, 6, 7
B. 7, 6, 5
C. 6, 5, 7
D. 7, 5, 6

990. “Rolling of a die” is an example of a random
A. event
B. outcome
C. experiment
D. sample space