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.
Quartile Deviation (Q. D.) is half of the difference between the first and third quartiles. Hence, it is called Semi Inter Quartile Range. In Symbols, Q. D = Q3 â Q1. Among the quartiles Q1, Q2 and Q3, the range Q3 Q1 is called inter quartile range and (Q3-Q1)/2, Semi inter-quartile range.