6.已知環(huán)比增長速度為2%、5%、6.1%，則定基增長速度為(      )

A.2%×5%×6.1%                                               B.(2%×5%×6.1%)-100%

C.102%×105%×106.1%                                    D.(102%×105%×106.1%)-100%

7.不受極端值影響的平均數(shù)有(      )

A.幾何平均數(shù)                                                  B.調和平均數(shù)和算術平均數(shù)

C.數(shù)值平均數(shù)                                                  D.中位數(shù)和眾數(shù)

8.若零售物價指數(shù)增長10%，零售商品銷售量增長5%，則商品零售額增長(      )

A.5.5%                                                            B.115.5%

C.15.5%                                                           D.105%

9.抽樣推斷的主要目的是(      )

A.計算和控制抽樣誤差                                    B.對問題作深入研究

C.計算抽樣數(shù)目                                               D.用樣本指標推斷總體參數(shù)

10.計算相關系數(shù)時，要求兩個變量為(      )

A.都是離散變量                                               B.都是確定變量

C.都是隨機變量                                               D.一個為隨機，一個為確定變量