Multiple Choice

1. An observation whose value changes is

a. a random variable.

b. discrete.

c. continuous.

d. a statistic.

2. A population with well-known characteristics is a __________.

a. statistic

b. sample

c. distribution

d. sample statistic

3. All of the following are measures of central tendency except _________.

a. mean

b. standard deviation

c. mode

d. median

4. The square of the standard deviation is the ___________.

a. variance

b. sigma

c. mode

d. skewness

5. About __% of the area under a normal distribution lies within two standard deviations of the mean.

a. 65%

b. 75%

c. 85%

d. 95%

6. Volatility is most closely associated with

a. the median.

b. the central limit theorem.

c. dispersion.

d. central tendency.

7. A distribution showing skewness is

a. not symmetric.

b. normal.

c. uniform.

d. triangular.

8. A standard normal distribution has

a. a mean of zero.

b. a mean of one.

c. a mean equal to the standard deviation.

d. a mean equal to the variance.

9. Two variables are independent if

a. they come from different distributions.

b. their correlation coefficient is negative.

c. their correlation coefficient is positive.

d. their correlation coefficient is zero.

10. Which of the following is true?

a. The correlation coefficient is always positive.

b. The absolute value of the correlation coefficient is always less than one.

c. Independent variables have a correlation coefficient not statistically different from zero.

d. Correlated variables are usually inversely related.