6.根據(jù)一定的研究目的，選擇一組研究對(duì)象，人為地改變與控制某些因素，然后觀察其后果。這種方法是（　　�。�

A.問(wèn)詢法                                                          B.觀察法

C.試驗(yàn)法                                                          D.文獻(xiàn)法

7.在研究對(duì)象的總體中，選取其中的重點(diǎn)單位進(jìn)行調(diào)查。這種方法是（　　�。�

A.普查                                                              B.重點(diǎn)調(diào)查

C.典型調(diào)查                                                       D.抽樣調(diào)查

8.可以做減法運(yùn)算，無(wú)法做除法運(yùn)算。這種測(cè)量水平是（　　�。�

A.定類尺度                                                       B.定序尺度

C.定比尺度                                                       D.定距尺度

9.關(guān)于抽樣誤差表述正確的是（　　�。�

A．抽樣誤差與估計(jì)精度無(wú)關(guān)

B.只有抽樣達(dá)到一定的數(shù)目，才能控制抽樣誤差

C.抽樣誤差與總體各單位的差異程度成反比

D.抽樣誤差與抽樣數(shù)目成正比

10.某銀行欲了解平均每戶活期存款余額和估計(jì)其總量，根據(jù)存折帳號(hào)順序，每50本存折抽出一本登記其余額。這種抽樣組織形式是（　　�。�

A.純隨機(jī)抽樣                                                  B.類型抽樣

C.等距抽樣                                                       D.整群抽樣

11.統(tǒng)計(jì)表的數(shù)字部分中符號(hào)“……”代表的含義是（　　�。�

A.某項(xiàng)數(shù)字不存在                                           B.缺少某項(xiàng)數(shù)字

C.某項(xiàng)數(shù)字較大                                                D.提醒注意核計(jì)

12.若間距h= 8-16，f_i=3,則m值為（　　�。�

A.12                                                                B.4

C.6                                                                   D.8

13.某公司職工年薪36000元的人最多，平均收入為35000元，則職工年薪的分布為（　　�。�

A.正偏                                                              B.負(fù)偏

C.對(duì)稱                                                              D.不能作出結(jié)論

14.上限與下限之差是（　　　）

A.組限                                                              B.組距

C.組中值                                                          D.等距

15.累計(jì)頻數(shù)分布曲線一般都呈（　　�。�

A.鐘型曲線                                                       B.U型曲線

C.J 型曲線                                                       D.邏輯斯蒂曲線