Question

（6分）某區為了解全區2800名九年級學生英語口語考試成績的情況，從中隨機抽取了部分學生的成績（滿分24分，得分均為整數），制成下表：

分數段（x分）	x≤16	17≤x≤18	19≤x≤20	21≤x≤22	23≤x≤24
人    數	10	15	35	112	128

1.（1）填空：

①本次抽樣調查共抽取了  ▲  名學生；

②學生成績的中位數落在  ▲  分數段；

③若用扇形統計圖表示統計結果，則分數段為x≤16的人數所對應扇形的圓心角為  ▲  °；

2.（2）如果將21分以上（含21分）定為優秀，請估計該區九年級考生成績為優秀的人數．

 

Answer 1

 

1.（1）①300················································································································· 1分

②21≤x≤22·········································································································· 3分

③12······················································································································ 4分

 

2.2）2800×=2240（人）      5分

解析:略