you and your lab partner are asked to determine the density of an aluminum bar. the mass is known accurately to 4 significant figures. you use a simple metric ruler to determine its size and calculate the results in column a. your partner (using a precision micrometer for the first time) obtains the results in column b. (the accepted density of aluminum is 2.702 g/cm3.)

method a results (g/cm3) method b results (g/cm3)

2.2 2.603

2.3 2.601

2.7 2.605

2.4 2.611

calculate the average density for each method.