Question

What is the first quartile (Q1) of the data set? 51, 42, 46, 53, 66, 70, 90, 70

80
59.5
61
48.5

Answer 1

Values in increasing order
42
46
51
53
66
70
70
90


Lower quartile : There are 8 observations
If there are in observations, compute the lower quartile as follows:
if n/4 is an integer, compute the lower quartile as
(x[n/4]+x[n/4+1])/2 :: (x[8/ 4]+x[8 /4 +1])/2
if n/4 is not an integer, compute the lower quartile as
x[k], where k is the smallest integer exceeding n/4:: 2 = 2
Lower Quartile : Average of observations 2 and 3 is --
= (46+51)/2 = 48