percent difference

  1. usehn

    How to get the Uncertainty of a percentage change

    I have a measurement with uncertainties for two years. Say Year 1 Rain : 100mm(80-120mm) Year 2 Rain : 120mm(103-131mm). Now I get the percentage change in rain in Year 2 w.r.t Year 1 as 20%. Is there a way to get the uncertainty associated with this percentage change?
  2. D

    Voltage change to go from 60-W to 50-W?

    In a "brownout" situation, the voltage supplied by the electric company falls. Assuming the percent drop is small, show that the power output of a given appliance falls by approximately twice that percent (assuming resistance does not change). How much of a voltage drop does it take for a 60-W...