甲、乙、丙三数的平均数为184,丁数为64,四个数的平均数是多少?
(184×3+64)÷4,
=616÷4,
=154;
答:四个数的平均数是154.
用所给词的正确形式填空
1.His grandpa _________ (die) ten years ago.
2.Look! Some students __________ (sing) to the music.
3.She will come back if she _________ (be) free.
4.They were pleased to see the _________ (move) film.
5.To my _________ (surprise), I can meet you here.
6.The _________ (two) lesson is the most difficult one.
7.Jim did the work _________ (well) of all the students.
8.Spaceships _________ (with) people have reached other parts of the universe.
9.Amy practices __________ (speak) Chinese for an hour every day.
10.Look! How __________ (beautiful) these pictures are!
什么是统计分布?