In a laboratory measuring the terminal speed of a steel ball falling through…
PHYSICS · Multi-part · Fermi University Physics · Scientific Practice & Experimental Methods · Records, communication and the epistemology of evidence · Records, communication and the epistemology of evidence
Measurement and Method, Ch Writing the result, and the integrity of the data behind it
Problem
In a laboratory measuring the terminal speed of a steel ball falling through glycerine, 40 independent timing runs were recorded in the raw data file. Run 23 was excluded from the analysis; the notebook entry for that day reads: "Run 23: ball visibly touched the tube wall before reaching the marked interval, timing invalid, excluded." The results were quoted both ways: with all 40 runs, v=(2.041±0.006)ms−1; with run 23 excluded (N=39), v=(2.045±0.004)ms−1 (both standard uncertainties, k=1). The criterion, the reason, and both numbers appear in the report. A classmate says: "Excluding any recorded reading is dishonest; a report should include every measurement that was actually taken."
((a)) Judge this claim, with reason.
((b)) List the four parts of the disclosure standard and confirm each is present here.
((c)) Using the same numbers, describe a way of presenting them that would make the exclusion indefensible.