Final answer:
The uncertainty in the mass is 1.95 kg.
Step-by-step explanation:
To calculate the uncertainty in your mass, you need to determine 3% of your mass. The uncertainty is calculated by multiplying your mass by 0.03 (3%).
Uncertainty = 65 kg * 0.03 = 1.95 kg
Therefore, the uncertainty in your mass is 1.95 kg.