figure A-4 Measures of central tendency in skewed distributions These two distributions of scores are asymmetrical, or skewed. Distribution (a) is positively skewed; its tail extends toward the higher, more “positive” values of the distribution. Distribution (b) is negatively skewed; its tail extends toward the lower, more “negative” values of the distribution. In a skewed distribution, the mean is no longer a useful measure of central tendency because it is influenced by extreme scores. In a skewed distribution, the mode or median is the most appropriate measure of central tendency.