Exploring data: graphs and numerical summaries

5.6.1 Quartiles for the SIRDS data

For the 23 infants who survived SIRDS, the ordered birth weights are given in Table 9. The first quartile is

qL = x (¼(23+1)) = x (6) = 1.720kg.

The third quartile is

qU = x (¾(23+1)) = x (18) = 2.830kg.