1. Significant Figures Always record data as accurately as you can (as many sig. figs. as method allows) The last digit of the value that you record should be estimated Do not round values until calculations are completed Examples Follow

2. Sig Figs Examples Addition and Subtraction –Use least # of decimal places –15.287+13.07= 28.36 Multiplying and Dividing –Use least # of sig. figs. –0.0387*1.0= 0.039 (100.8+0.524)*10.05 = 4 sig figs –100.8+0.524 = 101.3 –101.3*10.05 = 1018

3. Relative & Absolute %Error Precision Determination –How far are values off from each other –Standard Deviation OR –Relative % Error – = (largest – smallest)*100%/average Accuracy Determination –How far off from real value? –Absolute %Error – = (|experimental value – real value|)*100%/real value

4. Standard Deviation Error Analysis-how far the values differ from the averages (related to %relative error, precision) Normal Distribution Assumed Average  Normal S=  (  (x i -x) 2 )/(N-1) Give values as Average ± Std Dev