在1000个数据中，用适当的方法抽取50个作为样本进行统计，频数分布表中，54.5～
题型：单项选择题
问题：
在1000个数据中，用适当的方法抽取50个作为样本进行统计，频数分布表中，54.5～57.5这一组的频率是0.12，那么，估计总体数据落在54.5～57.5之间的约有( )。
A．6个
B．12个
C．60个
D．120个
题型：单项选择题
A sign is another kind of language. Here are some of them that you see on the roads.
Number One is a sign with the number thirty on it. When drivers see this sign, they must not go at more than thirty kilometers an hour. We see this sign when we are getting near a town. Number Two is a sign that we’re near a crossing. We must drive carefully. Number Three is a sign that there is a bend (拐弯) in the road. Again, we must drive slowly and carefully. It is not safe to go around a bend very fast. Number Four is a sign that there is another road coming in from the right. There is a junction (交叉) at this place. Number Five is a sign that there is a hill and Number Six is a sign that the road gets narrow. Drivers must go slowly and carefully. Number Seven has the word “SCHOOL” on it. This is a sign that there is a school at the side of the street or the road. Perhaps there are children going to or leaving school. So drivers must look carefully and go slowly. Number Eight is a sign with the letter “P” on it. The letter “P” means “Parking”. At some places, there are the signs “No parking” or “No waiting”. If a driver leaves his car near one of these signs, a policeman may come and write down the number of his car.
小题1:At the places where you see Sign 1, ____________.
A．you are already out of a town
B．you still have thirty kilometers to go
C．there must be many houses and buildings not far away
D．there must be a town thirty kilometers away小题2:A driver can leave his car ___________.
A．near a sign with “P” on it in the daytime
B．near a sign with “No parking” on it
C．near a sign with “No waiting” if there’re no policemen there
D．near Sign 8 at any time小题3:People put these signs on the roads to ____________.
A．make driving even safer
B．show drivers the way
C．stop cars going too fast
D．learn another kind of language