histogram中二教ga圖~
A histogram is acommon statistical graph.Data are presented by rectangular bars with no gaps in between and each bar is divided by its class boundaries. The bar of each class is denoted by its c-lass mark.-茶- 左面係frequency,下就係class mark~做完histogram,之後利用數據可以做埋frequency polygon,cumulative frequency polygon同cumulative frequency curve~不過histogram唔同bar chart,唔好搞亂~