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

80

59.5

61

48.5

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