1、什麽是T test?

t-test：比較數據的均值，告訴你這兩者之間是否相同，並給出這種不同的顯著性（即是否是因為偶然導致的不同）

The t test (also called Student’s T Test) compares two averages (means) and tells you if they are 
different from each other. The t test also tells you how significant the differences are;
In other words it lets you know if those differences could have happened by chance.
 

例子：制藥公司可能想測試一種新的抗癌藥物，看看它是否能提高預期壽命。在實驗中，總有一個對照組(給一組人服用安慰劑，或“糖丸”)。對照組的平均預期壽命為+5歲，而服用新藥的組的平均預期壽命為+6歲。看來這種藥可能有效。但這可能是一個巧合。為了驗證這一點，研究人員將使用Student’s t-test來發現結果是否可以在整個人群中重復

Student’s T-tests can be used in real life to compare means. For example, a drug company may 
want to test a new cancer drug to find out if it improves life expectancy. In an experiment, 
there’s always a control group (a group who are given a placebo, or “sugar pill”). The control
 group may show an average life expectancy of +5 years, while the group taking the new drug 
might have a life expectancy of +6 years. It would seem that the drug might work. But it could 
be due to a fluke. To test this, researchers would use a Student’s t-test to find out if the 
results are repeatable for an entire population.
 

2、The T Score.

T Score：是兩組之間的差異與組內差異的比值。t值越大，組間差異越大。t值越小，組間的相似性越大。t得分為3表示兩個組之間的差異是它們內部差異的三倍。當您運行t測試時，t值越大，結果越有可能是可重復的

The t score is a ratio between the difference between two groups and the difference within the
 groups. The larger the t score, the more difference there is between groups. The smaller the t
 score, the more similarity there is between groups. A t score of 3 means that the groups are 
three times as different from each other as they are within each other. When you run a t test, 
the bigger the t-value, the more likely it is that the results are repeatable
 

t檢驗，T Test (Student’s T-Test)