Median
Median–median line

This is a method of robust regression. The idea dates back to Wald in 1940 who suggested dividing a set of bivariate data into two halves depending on the value of the independent parameter x {\displaystyle x}: a left half with values less than the median and a right half with values greater than the median. He suggested taking the means of the dependent y {\displaystyle y} and independent x {\displaystyle x} variables of the left and the right halves and estimating the slope of the line joining these two points. The line could then be adjusted to fit the majority of the points in the data set.
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