guan yu DATA-BASED de wen ti ,hen jian dan,qiu ying yu da sh

guan yu DATA-BASED de wen ti ,hen jian dan,qiu ying yu da shen
A company wishes to know what proportion ofAustralians would support the introduction of a Goods and Services Tax (GST) onproducts purchased online.The introduction of this GST would result in onlinegoods being more expensive to purchase than what they are currently.Thecompany obtains the email addresses of 2,500 Australians who have shoppedonline through a particular internet site.An email is sent to each of thesepeople asking whether they would support the introduction of this GST.Even ifall 2,500 of the selected individuals respond truthfully to this email,what isthe most obvious form of bias here and the most likely potential consequence ofthis bias?
A.Anon-response bias where the proportion of individuals who respond saying thatthey support the introduction of this proposed GST would likely be less thanthe proportion of all Australians who support the GST.
B.Anon-response bias where the proportion of individuals who respond saying thatthey support the introduction of this proposed GST would likely be greater thanthe proportion of all Australians who support
C.Asampling bias where the proportion of individuals who respond saying that theysupport the introduction of this proposed GST would likely be less than theproportion of all Australians who support the GST.
D.Asampling bias where the proportion of individuals who respond saying that theysupport the introduction of this proposed GST would likely be greater than theproportion of all Australians who support the GST.
E.Noneof the above.
(2 marks)
Reasoning:
yao da an
Marking for this question will proceed as follows:if you circle
the `correct' answer according to the answer sheet then you will receive full
marks and your reasoning will not be assessed.However,if you circle a
different answer AND your reasoning is partly/fully convincing in terms of how
it should be the correct answer,then you will receive part/full marks.

试回答一下：
选C
Reasoning:
Firstly,I don't think there's response related bias,if all individuals respond truthfully to the email.And if the individuals are carefully selected,they can well represent the opinions of all Australians.But read from the above we learned that those individuals are selected from those " who have shopped online through a particular internet site".Since not all Australians shop online,they cannot rightfully represent all Australians.And I would assume that people who shop online for the bargain prices will not be happy with the introduction of GST which results in higher prices.Thus there's a sampling bias where the proportion of individuals who repsond to support GST would be less than that of all Australians who support the GST.
non-response bias 应该谈不上,因为从取样人群中看不出任何特殊人群有不回email的理由.但是由于取样人群是“曾在某特定网站购物的人”,首先并不是所有人都在网上购过物的,而且在某特定网站其实也是有偏向性的,这个取样就存在问题,是sampling bias.考虑到在网上购物的人喜欢货比三家、价廉物美的共性,他们其实是不喜欢加税的,所以其赞成加税的比例应比大众少.