期望值(Expectation)

1. 任何變數的期望值都是一個常數
2. 期望值不一定等於隨機變數會發生的值
3. 用來估算某個隨機變數的值
4. 根據大數法則，期望值等於平均值

Python Note 持續新增..

REPL:

_ : 代表互動環境中上一次運算結果
' ' : 包住的為字串值

Background:
1. Every .py is a module.

機率密度函數（Probability Density Function）

1. 機率密度函數在某區域上的積分為這隨機變量區域之內的機率。

Continual & Continuous 差別

Continual :
Frequency, 連續中間有間斷的

Continuous :
連續中間不間斷的

E.g.
Continual rain = 間斷的下雨
Continuous rain = 不間斷的一直下雨

have been to 和 have gone to 的差別

have been to + place
曾經去過
have gone to + place
去過並且還在那個地方

特殊用法 (逐漸新增)

for ages = 很長一段時間
outside the house
short of = 缺乏
put on = 穿上去的動作
soon after = 不久
The train I was on....
fair enough
Third time's charm
Shortly into Sth.
make up my mind
We might as well = We should do
start off = 一開始...
something is everything = 某事物就是一切(很重要的一件事)
cut back on something = 減少 削減
You have your work cut out for you = 一堆棘手的工作等著你
in excess = 過量
The likes of A and B = 像A和B這樣的人

Complex 和 Complicated的差別

Complex 說一件事物或現象的自然複雜性質"沒有在暗示是有人出錯或是做錯而造成的複雜性"
Complicated 通常是用在一件事物或現象的複雜是因為人為因素所造成的"可能有人去把它複雜化"比如說人際關係的複雜

參考: https://tw.answers.yahoo.com/question/index?qid=20110313000010KK00723

Assume & Presume 的差別

Assume = wild guess
Presume = educated guess

像是看到有人戴婚戒
我們會說:
I presume you are married.