Density Curves Frequency histogram- uses counts of items in each class Relative frequency histogram- uses percent of observations in each class Density curve- fits a curve to the data on a relative frequency histogram This means the total area under the curve is equal to 1.

Measures of Center on a Density Curve Mean- on a density curve is the point at which the curve would balance on a fulcrum Median- on a density curve is the equal areas point. Half the area under the curve is to the left of the median and half is to the right. When a density curve is symmetric, a normal curve, then the mean and median occur at the same point.

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