A laboratory report reads: "We measured the density of an aluminium block as
PHYSICS · Multi-part · Fermi University Physics · Scientific Practice & Experimental Methods · Data analysis and model fitting in the laboratory · Data analysis and model fitting in the laboratory
Measurement and Method, Ch Do two results agree? Comparison, consistency and outliers
Problem
A laboratory report reads: "We measured the density of an aluminium block as ρ=(2.50±0.20)×103kgm−3, an uncertainty of 8 per cent. The accepted value is ρ0=2.70×103kgm−3 (its uncertainty is negligible on this scale). Since our value agrees with the accepted value, our experiment was successful and our method has been validated."
((a)) Calculate the consistency ratio z between the measured and accepted values.
((b)) Find the error in the report's reasoning and rewrite the conclusion as one of the two permitted reporting sentences.