Change value range 2g or 4g or 8g or 16g

Hello i'm Sutani from  Indonesia, 

i want ask to your product DFrobot from wiki : https://wiki.dfrobot.com/Serial_6_Axis_Accelerometer_SKU_SEN0386, 
 

Question on product:

1. what is default range value on this product? 2g or 16g?

2. i want to change value sensitivity from default range to 2g?

3. Please  explain the code below 

a. what is 32768.000? and when i want to change another value range, how?
b. what is 16.000? and how when i want to change another value range, how?

c. what is 9.8? and when do i want to change another value range, how?

referring to the code,  library: https://github.com/DFRobot/DFRobot_WT61PC/blob/master/DFRobot_WT61PC.cpp

Thank you, 

Sutani.