Drawing a conclusion based on information presented is called an inference (:
Can you give some information , what book?
Answer:
There are several main criteria for determining whether a source is reliable or not.
1) Accuracy. Verify the information you already know against the information found in the source. Look also for disclaimers as to the accuracy of the content. You may also want to double-check the information against a source that you already know is trustworthy. Even though a source may use technical language, the content may be misleading.
That they are rich and poor that means more money and less money