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 ?
The advantage of SEF is deeper nulls, especially, the first null.
Figures 7 and 8 show the recovery of three nulls originally at angles of [[theta].
Now the recovery of six nulls for single element failure and SEF originally at positions 18[degrees], 31.
55 dB, which is the price to be paid to achieve deeper nulls including the first null.
Including null values within your data can have an adverse effect when using this data within any mathematical operations.
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].
To ensure that the Stock Value can always be calculated, you must first ensure that the Price and QuantityInStock fields can never contain a NULL value.
A further example of the effects of null values can be seen below:
The green line represents the null depth of the best chromosome and the orange line represents the average null depth for the entire population (16 chromosomes).
The adapted pattern has a large sidelobe at -45 [degrees] in addition to putting a null at +45 [degrees].
Figure 10 shows the adapted pattern for a null at 28.
The null was formed in four iterations or 40 power measurements.