2 The floor areas, \(x \mathrm {~m} ^ { 2 }\), of 20 factories are as follows. Represent these data by a histogram on graph paper, using intervals $$0 \leqslant x < 500,500 \leqslant x < 1000,1000 \leqslant x < 2000,2000 \leqslant x < 3000,3000 \leqslant x < 4000 .$$