If you were writing a range of values you expect a measurement to fall in, how would you write it most accurately and concisely? Say the range is 8 to 12 dBV.
"The expected value is 10 dBV ± 2 dB."
"The expected value is 10 dBV ± 2 dBV."
"The expected value is 10 ± 2 dBV."
I think "10 ± 2 dBV" is most concise. If the units were feet, it would be "10 ± 2 feet", not "10 feet ± 2 feet". When I look at the graph I'm writing about, the plotted values are all above 8 dBV and below 12 dBV, and the x-axis is labeled "dBV". I'm not saying the other two expressions are wrong, just not as concise.
