1. The interquartile range includes the following scores?
a. 50% of the un ranked scores
b. 25% of the ranked scores
c. 70% of the rank scores
d. 50% of the ranked scores
e. 70% of the un ranked scores
2. Summing (adding together) all the deviations from the mean produces the following value?
a. half the standard deviation
b. the standard deviation
c. 0
d. the mean value for the set of scores
e. the median value for the set of scores
3. Why does the standard deviation formula have a square root as part of it?
a. to make it add up to the mean
b. to reverse the effect of squaring the deviations
c. to provide a standard (i.e. mean=0; sd=1) unit of measure
d. to provide a smaller value
e. none of these
4. Which of the following Greek letters represents the mean of a population?
a. β
b. α
c. μ
d. ε
e. λ
5. Sigma squared represents?
a. Population variance
b. Sample standard deviation
c. Population standard deviation
d. Population range
e. Sample variance
6. For a set of data that follow a normal distribution how many scores can one expect to find within one standard deviation on each side of the mean, that is two standard deviations in total?
a. 54%
b. 99%
c. 50%
d. 88%
e. 68%
7. A sample of data is highly negatively skewed?
a. Standard deviations should never be used to report the spread of such scores.
b. Standard deviations are always the most appropriate measure to report the spread of such scores.
c. Dependent upon the Standard deviation values it may be an inappropriate measure to report the spread of such scores.
d. The degree of skewedness is irrelevant in deciding to use the standard deviation. e. In this instance the standard deviation should be divided by the number of scores to obtain a more valid measure.
