how we improve our knowledge in base foundation of stats and maths
The references are given on the course itself. There is a course by Andrew Ng which is a very popular course, you can follow them. You would need very basic level maths for this course.
I have some information, this might help you~>
Statistics is a collection of tools that you can use to get answers to important questions about data.
You can use descriptive statistical methods to transform raw observations into information that you can understand and share. You can use inferential statistical methods to reason from small samples of data to whole domains.