We give data set: 6,47,49,15,43,41,7,39,43,41,36, and we would like to find the quartiles of this data set. 1. First, arrange the data points in increasing order and give them a index to indicate their position in the data set. index 1 is the data point with the smallest value, index 2 is the data point with the second-lowest value, ete. 2. Find the index of the median to split the data set in two. 3. Split the lower half of the data in two to find the lower quartile and give Q1. 4. Split the second half in two to find the value of the upper quartile and Q3. 5. Calculate the interquartile range