The marks (out of 30) obtained by 15 students in a class test are:
12, 18, 7, 25, 30, 16, 9, 14, 22, 27, 19, 24, 11, 13, 21.
a. (i) Organise the data into a grouped frequency distribution table using class intervals 0–5, 5–10, 10–15, 15–20, 20–25, 25–30, 30–35.
b. (ii) How many bars will appear in the histogram drawn for this table?