Interpreting p-values

Brokk Toggerson

What did you measure?

You measured the probability that the difference between your two measurements is due to chance. If your p-value was 0.167 that means that there is a 16.7% chance that the discrepancy between your results is purely due to the random fluctuations present in all data. A 16.7% chance is equal to 1/6 or the same as rolling a 2 on a 6-sided dice (so pretty common).

In many fields, the threshold for publication is p < 0.05.

Applying this standard to our case means that if your p-value is less than 0.05, then you would publish a result that there is a discrepancy in measuring \vec{g} between a falling object and a pendulum. Since this is not what is expected, this would possibly be evidence for new, as yet not understood, laws of physics!


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Physics 132 Lab Manual by Brokk Toggerson is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, except where otherwise noted.

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