about economic

marginal means ADDITIONAL here.
for example,

MB MC
1 5 7
2 8 9
3 13 15
4 19 21
5 34 42

from the above figure, the marginal benefit for unit 5 is 15(34-19)and marginal cost is 21(42-21)

invisible hand is a method /term for allocating resources ----using price as the main allocation,it is mainly used in market economy with less government intervention

hope it can help you

benefit 同 cost 都可用不同概念黎考慮不同既野。不同概念指 total 總、average平均 和 marginal 邊際。三者完全不同。

例如我去搵工，要用時間、打扮、準備工夫等，是 cost；搵到的工、得到的 offer 是 benefit。

例子：你寄左一封信，去沙田見一次工搭左廿蚊車 (cost)，得到一份月薪 八千 的工 (benefit)。

如果你的搵工行動到此為此，接受左呢份工，你的total cost 是 $21.4 ，total benefit 是一份月薪八千的工。 由於只有一次，故此平均和總計都是一樣。第一個item 計marginal 亦無乜意義。

如果你唔接受呢份工，再寄信，今次去沙頭角見一次工搭左四十蚊車，呢次見工的使費是 $41.4 ，就是 marginal cost；呢個 marginal cost 加入之前的 cost 就是 total cost，即見兩份工的 total cost 是 $62.8。今次的 offer 是 月薪 $8500。marginal benefit 是兩個數的差距，即 8500-8000 = 500.

如果你都唔接受，再寄信，第三次去長洲見一次工搭車搭般用左七十蚊，marginal cost = ??? .... total cost = ??? .... 今次的 offer 是 月薪 $8750。marginal benefit = ???

從一般的角度分析：total benefit 上升，似乎應該繼續搵更高人工的工作，但這個例子也是簡化的，例如你用左時間黎搵工，其實放棄了早些返工所收的人工和經驗…等等。

經濟學有時用 marginal 的概念黎分析，例如：marginal cost不斷上升，而 marginal benefit 不斷下降，便不值得做了。通常，經濟學上的有效率 (efficient) 係指 marginal cost = marginal benefit



invisible hand 即無形之手，係指市場機制 (價格) 可以解決分配的問題。分配係用隻手黎分配的，價格就係果隻手；由於價格唔係真係有血有肉的一隻手，所以是無形之手。有血肉的手我指市府干預。著名經濟學家佛利民 (Milton Friedman) 果堆學者就信奉「小政府」主義，即政府不應干預市場，讓價格決定一切；公營事業減到最少…等等。 香港都算愈黎愈多干預，難怪有報道就 佛利民 年頭黎完香港之後激死左。 >_<


2007-07-17 22:51:18 補充：
如果你都唔接受，再寄信，第三次去長洲見一次工搭車搭般用左七十蚊marginal cost = 71.4 total cost = 71.4 62.8 = 134.2marginal benefit = 8750-8500 = 250

By N. Gregory Mankiw, one principle of economics under ten principles is &quot;Rational people think at the Margin&quot;.

You may view &quot;margin&quot; means &quot;edge&quot;. Margin means small incremental amount. benefit is the broad idea, which can be defined as &quot;total benefit&quot;, &quot;average benefit&quot;, &quot;marginal benefit&quot;, and even &quot;unanticipated benefit&quot;; so the cost does the same.

In Economics (PS: not Economic, remember to add &quot;s&quot; to show as a academic subject), we analyze people&#39;s behaviour by the marginal magnitude change with the corresponding &quot;marginal benefit and marginal expected cost&quot; for prediction, and marginal benefit and marginal cost for comparison.

What is &quot;margin&quot;? Actually, it means you will not think studying for the whole day, but, you will think at the margin --- should I study for an extra hour? That&#39;s the margin.

Invisible hand is first advocated by Adam Smith, in his text &quot;An Inquiry into the Nature of Causes of the Wealth of Nations&quot;. Invisible hand is somewhat market mechanism. Under market mechanism, millions of people interact with one another to maximize their own gain. In social improvement, people is led by an invisible hand to promote an end which was no part of his intention.