Define, then compare and contrast variance and standard deviation.
What will be an ideal response?
Ans: In a population, the variance is the average squared deviation from the mean, and in a sample, the variance is the sum of squared deviations from the mean divided by n – 1. For both populations and samples, the standard deviation is the square root of the variance. The variance and standard deviation are both useful measures of dispersion, and both are preferable to the range in that they make use of all scores in a sample or population. However, the standard deviation is a more intuitive measure of variability than the variance because it is more directly related to the separations between scores in a set.
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A property of measurement in which the ordering of numbers reflects the ordering of the variable is:
a. identity. b. magnitude. c. equal unit size. d. absolute zero.
EEGs are useful for measuring ____
a. ?electrical activity in large areas of the brain b. ?the structure and size of brain organs c. ?neurotransmitter activity between neurons in the nervous system d. ?blood flow in the central nervous system
Descriptions of disorders in the DSM-IV-TR
a. can be found for all forms of culture-bound syndromes. b. are derived from survey responses from board-certified clinicians in North America and Europe. c. are based on empirical data and clinical observations. d. are intentionally vague so that all known disorders can be categorized.
What type of gene is expressed even if it is paired with a recessive gene?
a. polymorphic gene c. genome b. zygote d. dominant