editing image and a text edit

1-Introduction/03-defining-data/README.md

@@ -38,7 +38,7 @@ Examples of unstructured data: HTML, CSV files, JavaScript Object Notation (JSON
 
 A data source is the initial location of where the data was generated, or where it "lives" and will vary based on how and when it was collected. Data generated by its user(s) are known as primary data while secondary data comes from a source that has collected data for general use. For example, a group of scientists collecting observations in a rainforest would be considered primary and if they decide to share it with other scientists it would be considered secondary to those that use it. 
 
-Databases are a common source and rely on a database management system to host and maintain the data where users use commands called queries to explore the data. Files as data sources can be audio, image, and video files as well as spreadsheets like Excel. Internet sources are a common location for hosting data, where databases as well as files can be found. Application programming interfaces, also known as APIs allow programmers to create ways to share data with external users through the internet, while the process of web scraping extracts data from a web page. The [lessons in Working with Data](/2-Working-With-Data) focuses on how to use various data sources. 
+Databases are a common source and rely on a database management system to host and maintain the data where users use commands called queries to explore the data. Files as data sources can be audio, image, and video files as well as spreadsheets like Excel. Internet sources are a common location for hosting data, where databases as well as files can be found. Application programming interfaces, also known as APIs allow programmers to create ways to share data with external users through the internet, while the process of web scraping extracts data from a web page. The [lessons in Working with Data](/2-Working-With-Data) focus on how to use various data sources. 
 
 ## Conclusion
 

1-Introduction/04-stats-and-probability/README.md

@@ -31,7 +31,7 @@ It is more difficult to describe the probability distribution of a continuous va
 
 We can only talk about the probability of a variable falling in a given interval of values, eg. P(t<sub>1</sub>&le;X&lt;t<sub>2</sub>). In this case, probability distribution is described by a **probability density function** p(x), such that
 
-<img src="http://www.sciweavers.org/tex2img.php?eq=P%28t_1%5Cle%20X%3Ct_2%29%3D%5Cint_%7Bt_1%7D%5E%7Bt_2%7Dp%28x%29dx&bc=White&fc=Black&im=jpg&fs=12&ff=arev&edit=0" align="center" border="0" alt="P(t_1\le X<t_2)=\int_{t_1}^{t_2}p(x)dx" width="228" height="51" >
+![P(t_1\le X<t_2)=\int_{t_1}^{t_2}p(x)dx](./images/probability-density.png)
   
 A continuous analog of uniform distribution is called **continuous uniform**, which is defined on a finite interval. A probability that the value X falls into an interval of length l is proportional to l, and rises up to 1.