For those of you who use something like google sheets, I made this to include the margin of error in my spreadsheet. (row 4 is what you want to be looking at, row 5 is just an example) It also makes it so the range can't go negative. Just drop your Hanna results into A4 and you're good to go!
B4) =A4*3.066/1000
C4) =MAX(ROUND(((A4-5)*3.066/1000)*0.95,3) , 0 )&" - "&MAX(ROUND(((A4+5)*3.066/1000)*1.05,3) , 0 )
Enjoy!
B4) =A4*3.066/1000
C4) =MAX(ROUND(((A4-5)*3.066/1000)*0.95,3) , 0 )&" - "&MAX(ROUND(((A4+5)*3.066/1000)*1.05,3) , 0 )
Enjoy!