# Basic Statistics MCQs

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6. The arithmetic mean of all possible outcomes is known as
(A) expected value
(B) critical value
(C) variance
(D) standard deviation

7. Which of the following cannot be the value of a correlation coefficient?
(A) –1
(B) –0.75
(C) 0
(D) 1.2

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

9. 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)

10. 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

6. (A) expected value
7. (D) 1.2
8. (D) E[X2] – E[X]2
9. (C) Var(X) + Var(Y) + 2 Cov(X, Y)
10. (B) 17.5

SOLUTIONS: BASIC STATISTICS MCQS

6. Expectation (or expected value) is the arithmetic mean of all possible outcomes of a random variable.

7. The value of a correlation coefficient is always between –1 and 1, including –1 and 1.

8. By definition, Var (X) = E[X2] – E[X]2

9. By definition, Var (X + Y) = Var(X) + Var(Y) + 2 Cov(X, Y)

10. First calculate the mean Now calculate the variance, 