Tin has long been used in alloys with lead as solder, in amounts 5 to 70% w/w. Tin with lead forms a eutectic mixture at the weight proportion of 61.9% tin and 38.1% lead (the atomic proportion: 73.9%
The first quartile (Q 1) is defined as the middle number between the smallest number and the median of the data set.
Definition of Quartiles. Quartiles are values that divide a set of data into four equal parts. 1  A data set has three quartiles: the lower quartile, the median of the data set, and the upper quartile.  Median: The median divides a data set into two equal parts.