Skewness is a measure of the extent to which the probability distribution of a random variable lies more to one side of the mean, as opposed to it being exactly symmetrical.
If μ and s are the mean and standard deviation of a random variable X, then
Skew(X) = Expected value of [(X - μ)/s]3
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Skewness is a measure of the asymmetry in a distribution. In a non-symmetrical distribution, skewness can be calculated using a formula that considers the deviation of each data point from the mean. A positive skewness indicates a longer tail on the right side of the distribution, while a negative skewness indicates a longer tail on the left side.
If a random variable X has mean value m, and standard deviation s, then Skewness = E{[(x - m)/s]3} which can be simplified to skewness = [E(X3) - 3ms2 - m3]/s3 and for discrete X, E(X3) = sum of x3*Prob(X = x) where the summation is over all possible values of x. While for continuous X, E(X3) = integral of x3*f(x) where the integral is over the domain of X.
Skewness is a measure of symmetry, or more precisely, the lack of symmetry. A distribution, or data set, is symmetric if it looks the same to the left and right of the center point. Kurtosis is a measure of whether the data are peaked or flat relative to a normal distribution. See related link. By doing a search on the internet, you can find more examples.
how do i find the median of a continuous probability distribution
Given a Poisson distribution with mean = 2. Find P(X < 5)
You would need to take repeated samples, find their median and then calculate the standard error of these values.