I am a doctor with limited mathematics knowledge. I am trying to prove to my medical fraternity that for a given force of aspiration, a smaller syringe generates a higher "negative pressure". I did a small experiment. I hung an one kilogram weight on a 5 ml and 10 ml syringe and connected it to a Digitron electronic manometer. I got the following neg pressure readings (cm Hg). The 5 ml syringe: 57.3;55.8;56.7;56.6;55.9;56.6;57.4;56.1;56.1;56.6 The 10 ml syringe gave the following: 32.8;32.3;30.7;31.9;31.9;32.6;30.6;33.3;32.1;30.5 I would like to"scientifically" say that the smaller syringe creates a bigger negative pressure. Would a "Students t" test be an appropriate one to use ? Can I use MS excel do do the test ? With regards to the posting by light_bulb: for each reading , i gave a 30 second time period for the readings to settle. Hopefully that will look after the time aspect of things ?