【单选题】同一品种的石油沥青材料牌号越( ) , 则黏性越小,针入度越大,塑性越好,延度越大,温度敏感性越大,软化点越低 。
【简答题】By stop spoiling their children, parents tried to adjust children to their future life with________
【单选题】Toys have several functions except______.
A.
helping children to play
B.
urging children to play
C.
recommending ways for children to play
D.
asking children to play
【多选题】下列关于抽样误差的说法,正确的有( )。
C.
无论是概率抽样还是非概率抽样,都能够比较精确地估算出抽样误差
D.
一般来说,抽样误差主要取决于总体的异质性程度和样本规模