Calculate the value of k.

Find

(i)     the median;

(ii)    the interquartile range.

evidence of using $\sum {{f_i} = 100}$     (M1)

$k = 4$     A1     N2

[2 marks]

(i) evidence of median position     (M1)

e.g. 50th item, $26 + 10 + 20 = 56$

${\text{median}} = 3$     A1     N2

(ii) ${Q_1} = 1$ and ${Q_3} = 5$     (A1)(A1)

${\text{interquartile range}} = 4$ (accept 1 to 5 or $5 - 1$ , etc.)     A1     N3

[5 marks]

Frequencies and median seemed well understood, but quartiles and inter-quartile range less so.

Frequencies and median seemed well-understood, but quartiles and interquartile range less so. A few students, probably based on past papers, drew cumulative frequency diagrams, generating slightly different answers for median and quartiles.