A simple robust scale estimator is the interquartile range, which is the difference between the upper and lower quartiles. For a normal population, the standard deviation can be estimated by dividing ...

Quartiles are the values that divide a data set into quarters: Put the values in order Divide the list into four equal parts The Quartiles are at the divisions The interquartile range shows the ...

is the middle number which divides the data into two halves. Similarly, the lower quartile \({Q_2}\) divides the bottom half of the data into two halves, and the upper quartile \({Q_3}\) ...