Shape+of+Frequency+Distribution

Shape of Frequency Distribution

Above is a __Symmetrical Distribution__ in which the data is evenly distributed around one point, which is representative of the mean, median, and mode (in the above case, A denotes this point). Above is a __Positively (Right) Skewed Distribution__ in which there is a small number of data in which the "scores" are unusually high, such as only a few students in a class of 20 receiving an A, while the rest of the class receives D's and F's. Above, point A denotes the mode, B denotes the median, and C denotes the mean. In this case, an outlier could throw off the accuracy of the mean. Above is a __Negatively (Left) Skewed Distribution__ in which the majority of the data represents high "scores" with a few low score outliers. Consider the classroom again, in this case, the majority of students received A's with one or two receiving D's or F's. Above, point A denotes the mean, B denotes the median, and C denotes the mode.

Using a box plot can also be useful when determining skewed information. If the box is to the right or the left, or if the median line is not equidistant from the Q1 and Q3 hinges, then the data set is skewed. The histogram for that data set will not be symmetrical.

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