which are topic of statistics every trader must understand clearly ?

[leecarter]

please also suggest good statistics book with easy language .

 

[afin]

Go for this -

https://www.discoveringstatistics.com/

 

[Mearelyemi]

any trading statistics need to be understood for successful work in the future

 

[mastermind007]

Risk-to-Reward Ratio
Win-to-Loss Ratio
Cost-to-Profit Ratio

are three basic universal stats that you need to understand. Other than that, there are infinite other parameters each important in different circumstances.