其中正確的個(gè)數(shù)為( )
①這組數(shù)據(jù)的眾數(shù)是8;
②這組數(shù)據(jù)的中位數(shù)是7;
③這組數(shù)據(jù)的平均數(shù)是7;
④這組數(shù)據(jù)的方差是2.2
成績(jī)(次) | 9 | 8 | 6 | 5 |
人數(shù)(名) | 2 | 3 | 3 | 2 |
根據(jù)圖中信息,解答下列問(wèn)題:
②補(bǔ)全條形統(tǒng)計(jì)圖(要求在條形圖上方注明名數(shù));
③扇形統(tǒng)計(jì)圖中圓心角 ▲ 度;