A factory recorded the number of defective bulbs in each of several production batches. The data are shown below. Each class represents exactly one value.
Defective bulbs per batch | 0–0 | 1–1 | 2–2 | 3–3 | 4–4 | 5–5
Frequency | 2 | 6 | 11 | 8 | 5 | 3
(i) State the lowest number of defective bulbs observed.
(ii) State the highest number of defective bulbs observed.
(iii) Calculate the range of the number of defective bulbs per batch.