The following table shows monthly wages of 10 workers. Calculate lower and upper quartiles.
Monthly wages 120,150,170,180,181,187,190,192,200,210.
Calculation of Lower and Upper Quartiles
N = 10
Q_{ 1 } = Size of(n+1/4) th item
= Size of (10+1/4) th item = Size of 2.75th item
= 2nd item + 0.75 (size of 3rd item - size of 2nd item)
= 150 + 0.75 (170-150) = 165
Q_{ 1 } = 165
Q_{ 3 } = Size of 3(n+1/4) th item
= Size of 3(10+1/4) th item = Size of 8.25th item
= 8th item + 0.25 (size of 9th item - size of 8th item)
=192 + 0.25(200-192)=194
Q_{ 3 } = 194