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What Is Skewness?, Skewness refers to distortion or asymmetry in a, symmetrical bell curve, or normal distribution, in a set, of data. If the curve is shifted to the left or to the right,, it is said to be skewed. Skewness can be quantified as a, representation of the extent to which a given, distribution varies from a normal distribution. A, normal distribution has a skew of zero, while a, lognormal distribution, for example, would exhibit, some degree of right-skew., The three probability distributions depicted below are, positively-skewed (or right-skewed) to an increasing, degree. Negatively-skewed distributions are also, known as left-skewed distributions. Skewness is used, along with kurtosis to better judge the likelihood of, events falling in the tails of a probability distribution., Scanned by CamScanner

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If one tail is longer than another, the distribution is skewed. These, distributions are sometimes called asymmetric or asymmetrical, distributions as they don't show any kind of symmetry. Symmetry, means that one half of the distribution is a mirror image of the other, half. For example, the normal distribution is a symmetric distribution, with no skew. The tails are exactly the same., A normal curve., A left-skewed distribution has a long left tail. Left-skewed, distributions are also called negatively-skewed distributions. That's, because there is a long tail in the negative direction on the number, line. The mean is also to the left of the peak., A right-skewed distribution has a long right tail. Right-skewed, distributions are also called positive-skew distributions. That's, because there is a long tail in the positive direction on the p..--L -, Scanned by CamScanner

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Mode, Mode, Median, Median, Mean, Mean, Scanned by CamScanner

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Mean and Median in Skewed, Distributions, In a normal distribution, the mean and the median are the same, number while the mean and median in a skewed distribution, become different numbers:, A left-skewed, negative distribution will have the mean to the left of, the median., Mean, Median, Scanned by CamScanner

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A right-skewed distribution will have the mean to the right of the, median., Mean, Median, Right skewed distribution: Mean is to the right, Effects on Statistics, The normal distribution is the easiest distribution to work with in, order to gain an understanding about statistics. Real life, distributions are usually skewed. Too much skewness, and many, statistical techniques don't work. As a result, advanced mathematical, techniques including logarithms and quantile regression techniques, are used. Read more about quantile regression here., Scanned by CamScanner