STATISTICAL TECHNIQUES AND TOOLS
MEASURES OF VARIABILITY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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All scores are identical.
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The mean of the scores is zero.
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The measure of variability cannot be computed.
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Half of the scores are additive inverse of the remaining half.
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Detailed explanation-1: -MathStatisticsWhen you compute for the measure of variability of a set of scores and it turns out to be zero, which of these could be said of the scores? A. All scores are identical.
Detailed explanation-2: -The standard deviation is the average amount by which scores differ from the mean. The standard deviation is the square root of the variance, and it is a useful measure of variability when the distribution is normal or approximately normal (see below on the normality of distributions).
Detailed explanation-3: -Standard deviation (SD) is the most commonly used measure of dispersion. It is a measure of spread of data about the mean. SD is the square root of sum of squared deviation from the mean divided by the number of observations. This formula is a definitional one and for calculations, an easier formula is used.