Null Result

In science, a null result is a result without the expected content: that is, the proposed result is absent. It is an experimental outcome which does not show an otherwise expected effect. This does not imply a result of zero or nothing, simply a result that does not support the hypothesis. The term is a translation of the scientific Latin nullus resultarum, meaning "no consequence".

In statistical hypothesis testing, a null result occurs when an experimental result is not significantly different from what is to be expected under the null hypothesis. While some effect may in fact be observed, its probability (under the null hypothesis) does not exceed the significance level, i.e., the threshold set prior to testing for rejection of the null hypothesis. The significance level varies, but is often set at 0.05 (5%).

As an example in physics, the results of the Michelson–Morley experiment were of this type, as it did not detect the expected velocity relative to the postulated luminiferous aether. This experiment's famous failed detection, commonly referred to as the null result, contributed to the development of special relativity. Note that the MMX did in fact appear to measure a non-zero "drift", but the value was far too small to account for the theoretically expected results; it is generally thought to be inside the noise level of the experiment.

Other articles related to "null result, results, result, null":

Kennedy–Thorndike Experiment - Theory - Consequences For Relativity
... In general, its null result requires that the ratio between transverse and longitudinal lengths corresponds to the Lorentz factor – which includes infinitely many combinations of ... Combining this value for α with the Kennedy–Thorndike null result shows that β necessarily must assume the value of relativistic length contraction ... And combining this value for β with the Michelson–Morley null result shows that δ must be zero ...
Dayton Miller - Scientific Contributions - Aether Research
... as the earlier Michelson-Morley experiment, Miller and Morley published another null result in 1904 ... These experimental results were later cited in support of Albert Einstein's theory of relativity ... of drift With white light and 32 m arms he could see nearly always the same result These results were presented by Miller as a positive indication of the existence of an aether ...
Null (SQL) - Comparisons With NULL and The Three-valued Logic (3VL) - Effect of Null and Unknown in Other Constructs - CASE Expressions
... same rules as the DML WHERE clause rules for Null ... Thus, a simple CASE expression cannot check for the existence of Null directly ... A check for Null in a simple CASE expression always results in Unknown, as in the following SELECT CASE i WHEN NULL THEN 'Is Null' -- This will never be ...
Timeline Of Luminiferous Aether - Timeline - Crisis
... 1887 – the Michelson-Morley experiment (MMX) produces the famous null result ... proposes the Contraction Hypothesis, which suggests that the measurements are null due to changes in the length in the direction of travel through the aether ... conduct a number of MM experiments with a 100 ft interferometer, producing the null result ...
Argument From Ignorance - Related Terms - Null Result
... Null result is a term often used in the field of science to indicate evidence of absence ... A search for water on the ground may yield a null result (the ground is dry) therefore, it probably did not rain ...

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