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.
Inter quartile range is defined as the difference between the third and the first quartile. Quartiles are the partitional values which divide the whole series into 4 equal parts. So, there are 3 quartiles. First Quartile is denoted by $Q_{1}$, second Quartile denoted by $Q_{2}$ and third Quartile denoted by $Q_{3}$.