Since there is an even number of values<span>, we </span>need<span> the mean of the middle two </span>values<span> to find the first </span>quartile<span>: </span>The lower<span> half of a </span>data set<span> is the set of all </span>values<span> that are to the left of the median </span>value<span>when the data has been put into increasing order.
