(Ⅰ)频率为0.025 × 10 = 0.25,频数为60 × 0.25 = 15.
(Ⅱ)这次数学竞赛的平均成绩是70.5
(Ⅲ)这次数学竞赛的及格率是0.75
(Ⅰ)频率为0.025 × 10 = 0.25,频数为60 × 0.25 = 15.
(Ⅱ)平均成绩为
.
(Ⅲ)0.015 × 10 + 0.03 × 10 + 0.025 × 10 + 0.005 × 10 = 0.75.
(Ⅰ)频率为0.025 × 10 = 0.25,频数为60 × 0.25 = 15.
(Ⅱ)这次数学竞赛的平均成绩是70.5
(Ⅲ)这次数学竞赛的及格率是0.75
(Ⅰ)频率为0.025 × 10 = 0.25,频数为60 × 0.25 = 15.
(Ⅱ)平均成绩为
.
(Ⅲ)0.015 × 10 + 0.03 × 10 + 0.025 × 10 + 0.005 × 10 = 0.75.