How to interpret a sensor input with analogReadSerial

I recently got a box from dfrobot that has tons of different sensors in it (temperature, light, acceleration, moisture, etc.) I've been wanting to use them, but am confused as to how to interpret the data I receive from the serial monitor.
Basically, is the data output linear, or does it follow some curve that is found on a datasheet? For example, say I have an accelerometer that can measure up to 1g. If it is accelerated by 1g, will the serial monitor output read 1023, And if it undergoes 0g's of acceleration, will it output 0 to the serial monitor? And, say it experiences .5g's of acceleration, will the serial monitor read 511?
Basically, how do I interpret the numbers being output without having to experimentally determine what output values mean?
Thanks!

Basically, how do I interpret the numbers being output without having to experimentally determine what output values mean?

Consult the data sheet for each sensor. Each one will state the factor or "sensitivity" that converts the output into standard units.