The Vernier sensor block for LEGO MINDSTORMS EV3 includes an option for oversampling. Oversampling takes a large number of samples and returns an averaged reading. This is a good feature to use when you need a steady, stable reading. Note that oversampling slows down how quickly readings are returned (about one every half-second), but this is a good option to choose when you are displaying sensor readings on the EV3 window.

Find the Vernier sensor block for EV3 here:
https://www.vernier.com/engineering/lego-ev3/ev3-sensor-block/

LEGO^® MINDSTORMS^® Education EV3 Core Set with Charger (LEGO-EV3-CORE)
NXT Sensor Adapter (BTA-NXT)
Vernier Engineering Projects with LEGO® MINDSTORMS® Education EV3 (EP-EV3-E)
LEGO® Mindstorms® EV3 Troubleshooting and FAQs