Put the data points in numerical order. The middle one will be the median (Q2). The middle number between the first and Q2 will be Q1. Q3 will be the middle number between Q2 and the highest number. If there is a even number of data points (so there is not a single number in the middle) then take the 2 numbers add and divide by 2.

Ex.

Data points: 1, 1.6, 1.8 , 2.3, 2.7, 3.4, 3.6

Q2 = 2.3

Q1 = 1.6 + 1.8 / 2 = 1.7

Q3 = 2.7 + 3.4 = 3.05

Feb 4th, 2015

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