Hi,
Sure? You want the thermistor range from 0 to 3V?
I assume there is a 10 bit ADC. So the result is 0...1023.
For ratiometric measurements mind to use same low pass filters on VRef and signal.
If you use only 0..99 of an 10 bit ADC, then the input voltage range is only 0...0.5V
Shifting the result to the right enables you to use input voltages 0..1V, 0..2V, or 0...4V.(about)
Using a simple multiplication enables you to adjust the range very precisely to your needs.
Klaus