Every time I write an expository writing, what my middle school Chinese teacher taught me always appear in my mind, use data to prove what you write. And it is common to see the statistics appear in reports, speeches, news etc. Data seems to be strong evidence; however, will it lie to the readers? Last weak, I read an article, which mainly talked about a group of people drive a particular cars. For proving that, the whole article is full of data. The logic of the writer is really easy to follow, after reading, I felt what he said is a fact. But think it deeper, where did he get the data? Is the sample large enough? Those were not shown in the article, and even though these two conditions are met. Do there any relations between what kind of person you are and what kind of car you drive? There are a lot of factors that will influence people to choose their job. Buying cars is a personal decision; it might relate to people’s job (salary), but it not the only thing that makes people choose their own cars. And we do not have evidence to prove there is a direct relationship between what kinds of person you are and what cars you drive. The data can lie.

The similar example also appeared in the ib math sl book when we studied the co-relation. There is a question, which ask us what conclusion can we get from the table. And the table shows the people who received more education will receive higher salary in their career. However, it is one’s capability to decide how much money they can earn as well as the education they received. Some people even did not go to the college, but they still earn more money than those college graduates. Those exceptions also show it is one’s capability to decide the salary they can earn. Therefore, theoretically, the result we get from the data is correct. In real life, this result is illogic and irresponsible.

My cousin used to tell me a joke. An expert did a research on which place has the highest number of the cancer patients and the result is a small island. Most people will tend to believe there must be some pollution there, or the people who live there are have genetic defect. But the truth is the sights in that island is very beautiful, and those cancer patients believe if they live there, they will be healthier. From the mathematical perspective, this data that have strong co-relation can be powerful evidence. And because of the inertial thinking, we will not pay a lot attention to what is the real causation or are there any direct relationship. Sometimes we will even misunderstand the causality by the language and data that writer use, it makes a big difference and lead to an inaccurate conclusion.

The statistic and real life sometimes cannot be well connected. Compare to those theoretical knowledge, real life is changeable. That is why when many theories applying to the real world, they might not work. So, to what extend can we use the theory? What is the value of theories? In addition, when we see the evidence that others show to us, we should always think it rationally rather than only simply follow others’ thinking.