Zero result
In science, a zero result describes a result of an experiment or an empirical survey that does not make the expected statement. Despite the name, it does not mean that nothing has been measured, just that the hypothesis that has been put forward has not been confirmed.
In a statistical test , a zero result means that the result does not differ statistically significantly from the null hypothesis . Due to random fluctuations, a deviation can certainly be observed. However, this is so small that it is very likely that it was generated by chance. It is precisely this probability that is estimated using the test. If it falls below a certain threshold, the significance level (usually 0.05 or 5%), the result is assumed to be significant. A zero result, on the other hand, means that this value was not fallen below.
Since most experiments and surveys are subject to considerable random fluctuations, a zero result cannot generally be regarded as proof that the effect under study does not exist - it just means that the measurement could not prove it. If an actually existing effect is not recognized by a measurement, one speaks of a false negative result.
A famous example of a null result is the Michelson-Morley experiment . This physical experiment was supposed to prove the speed of the earth relative to the so-called light ether , which was then accepted as the carrier medium for light. From the measurement results it was possible to calculate non-vanishing speeds, but these were far too low to be compatible with the ether theory. Later, more accurate experiments suggested that these results from the Michelson-Morley experiment could be explained by experimental inaccuracies. The experiment was an important step on the way to discarding the ether theory and replacing it with Einstein's special theory of relativity .
Individual evidence
- ↑ As an example of usage: C. Giunti, et al. : New ordering principle for the classical statistical analysis of Poisson processes with background . In: Phys. Rev. D . 59, No. 5, 1999, p. 053001. doi : 10.1103 / PhysRevD.59.053001 .
- ^ T. Roberts (2007), Relativity FAQ, What is the experimental basis of Special Relativity?