A report on a wire's resistivity states: "Raw data: measured resistances

PHYSICS · Subjective · Fermi University Physics · Scientific Practice & Experimental Methods · Data analysis and model fitting in the laboratory · Records, communication and the epistemology of evidence

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Problem

A report on a wire's resistivity states: "Raw data: 4040 measured resistances, tabulated in Appendix A. The graph of resistance against length shows the fitted line R=mL+c0R = mL + c_0, giving χν2=1.1\chi^2_\nu = 1.1 for ν=33\nu = 33." The appendix table lists exactly 4040 rows, and no other text in the report mentions any exclusion. (a) Using ν=Nfit−2\nu = N_{\text{fit}} - 2 for a two-parameter straight-line fit, find the number of points NfitN_{\text{fit}} actually used in the fit shown on the graph. (b) State the error in the report and what must be added for the graph to be regenerable from the data given.

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