(1)作出茎叶图如图所示;
(2)=(12+11+9+8+25+18+23+14)=15, =(22+25+10+5+13+10+20+15)=15, s甲2= | ((12-15)2+(11-15)2+(9-15)2+(8-15)2+(25-15)2+(18-15)2+(23-15)2+(14-15)2)= |
| | , s乙2= | ((22-15)2+(25-15)2+(10-15)2+(5-15)2+(13-15)2+(10-15)2+(20-15)2+(15-15)2)= |
| | , ∵=,s甲2<s乙2, ∴甲的成绩较稳定, ∴派甲参赛比较合适. |