null


Also found in: Dictionary, Thesaurus, Legal, Financial, Acronyms, Idioms, Encyclopedia, Wikipedia.
Related to null: null space

null

Molecular biology
See Null mutation.

Statistics
Completely absent; a set with no members or of zero magnitude. If a field has a value of null, it means that the value is unknown. A null value is not the same as a value of zero, and the difference can be crucial. For example, when calculating the average value of a field among many records where one row contains a zero, the zero gets factored into the average; if the field has a null value, it does not get factored in to the average.
References in periodicals archive ?
Abbreviations: ACTH, adrenocorticotroph adenoma; GH, growth hormone adenoma; GH+, Pit-1 family member with strong growth hormone and a lesser degree of prolactin or thyroid-stimulating hormone (TSH) staining; Gon, gonadotroph adenoma; Null, null cell adenoma; Pit1, Pit-1 family member (not otherwise specified); PlurGH, plurihormonal growth hormone adenoma; PlurGH+, plurihormonal growth hormone adenoma with lesser degrees of prolactin or TSH staining; PRL, prolactinoma; PRL+, Pit-1 family member with strong prolactin staining and lesser degree of growth hormone or thyrotropin staining; TSH+, TSH-producing adenoma with lesser degree of GH staining; Unk, unknown.
If the results of these [N.sub.0] hypothesis tests are statistically independent, then the probability distribution for the number of erroneously rejected null hypotheses will be binomial, yielding the probabilities for the possible numbers of erroneously rejected tests x,
This means that the null hypersurface ([H.sub.u], [h.sub.u]) is conformal to a fixed null hypersurface (H,[gamma]); that is, [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], with the conformal function [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].
Null recommends that, in addition to the dietary and supplement changes, individuals exercise actively.
One can clearly monitor from Figure 1 that due to single sensor failure the radiation pattern is damaged in terms of sidelobe levels, null depth, and displacement of the nulls from their original position.
A sample of the apparent TPOX null allele carriers who were identified in the way described above were re-profiled using the COfiler or Identifiler kits, which use different primers to those employed in the Powerplex 16 kit.
When you run the queries in the macro, zeros will be entered into the fields instead of nulls.
2, that due to single element failure the radiation pattern is damaged in terms of sidelobe levels, null depth and displacement of the nulls from their original position.
Consequently, the position vector of the null osculating curve of the first and second kind satisfies respectively the equations
Curry also suggests that the desire to reverse the null hypothesis may have the goal of seeking to marginalize the climate skeptic movement, a vocal group that has challenged the scientific orthodoxy on climate change.
In this case, [kappa] can take only two values: [kappa] = 0 when [alpha] is a null straight line, or [kappa] = 1 in all other cases.