null

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null

(nul)
1. insignificant; having no consequence or value.
2. absent or nonexistent.
3. zero; nothing.

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.

null

an absence of information, as contrasted with zero or blank or nil, about a value.

null cell
called also null lymphocyte; see null cell.
null hypothesis
a statistical hypothesis which states that one variable has no association with another variable, or set of variables. That is, the observed results can be explained by chance alone.
null lymphocyte
see null cell.
References in periodicals archive ?
You can see an example of the problem that null values cause when looking at certain records in this table, the Stock Value field derives its results by using the Price and the QuantityInStock value ['Price]*[QuantityInStock].
The two null values suggest that the population value is zero, so it was decided to perform a confirmatory single-mean t-test for the 20-trial case, with the subject as the unit of analysis and MCE of zero.
Using the case-only methodology, we observed that risk for ALL associated with exposure to total THM was elevated among children homozygous for GSTT1 deletion (null genotype) but below the null value with exposure to bromoform; risks for those carrying the CYP2E1 variant G-1259C (allele *5) were elevated for exposure occurring during the prenatal as well as the postnatal period.
lt;p>One warning on the tool: If you open a payload's settings and don't close it (click the minus icon), the profile includes all the null values for that payload, which essentially prevents users from accessing those settings.
Finally, we will discuss the challenge with null values when trying to create totals on a report.