The following table shows the monthly wages of 10 workers

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