2. The time between arrival of 60 patients at an intensive care unit were recorded to the

nearest hour. The data are shown below.

Time (hours) 0–19 20–39 40–59 60–79 80–99 100–119 120–139 140–159 160–179

Frequency 16 13 17 4 4 3 1 1 1

Determine the;

(a) median (3 marks)

(b) Third quartile (3 marks)

(c) 72nd percentile. (3 marks)

3. For the grouped frequency distri​