frequency distribution

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1. the specific location or arrangement of continuing or successive objects or events in space or time.
2. the extent of a ramifying structure such as an artery or nerve and its branches.
3. the geographical range of an organism or disease.
frequency distribution in statistics, a mathematical function that describes the distribution of measurements on a scale for a specific population.
normal distribution a symmetrical distribution of scores with the majority concentrated around the mean; for example, that representing a large number of independent random events. It is in the shape of a bell-shaped curve. Called also gaussian distribution. See illustration.
 Normal distribution. The approximate percentage of the area (or frequency) lying under the curve between standard deviations is indicated. From Dorland's, 2000.
probability distribution a mathematical function that assigns to each measurable event in a sample group the probability that the event will occur.

fre·quen·cy dis·tri·bu·tion

a statistical description of raw data in terms of the number or frequency of items characterized by each of a series or range of values of a continuous variable.

frequency distribution

A table or histogram showing the number of times each value of a particular variable occurs in a sample.
Frequency distributionclick for a larger image
Fig. 166 Frequency distribution . A distribution based on 9 numbers.

frequency distribution

an arrangement of statistical data in order of the frequency of each size of the variable. For example, the numbers 2,3,5,3,4,2,1,3,4 would have the frequency distribution shown in Fig. 166. Data from a large sample often produces a NORMAL DISTRIBUTION CURVE.


the arrangement of numerical data. The arrangement may be in accordance with magnitude, a frequency distribution, or in relation to geographical location, a spatial distribution.

age distribution
see age distribution.
bimodal distribution
the distribution has two regions of high frequency of observations separated by a zone of low frequency.
binomial distribution
a probability distribution associated with two mutually exclusive outcomes.
cluster distribution
a nonrandom distribution with observations aggregating about geographic or temporal variables. May be deceptive and merely reflect the distribution of an uneven population.
frequency distribution
a table or graph of the frequency of occurrence of each value of a variable.
Gaussian distribution
see normal distribution (below).
hypergeometric distribution
may apply to sampling without replacement of a finite population.
lognormal distribution
a distribution which is normal when the log values of the variable are considered.
normal distribution
a graph of the distribution appears as a bell-shaped curve which is symmetrical on the two sides of the vertical axis through the peak of the curve. Called also gaussian distribution.
parent distribution
the distribution (population) that was originally sampled.
Poisson distribution
regular distribution
distributed at regular intervals of time or space; all values within its given interval are equally likely.
sex distribution
an increase in frequency in one sex, which includes neutered males and neutered females. Called also sex-linked or sex-associated.
skewed distribution
a distribution in which the curve illustrating it is not symmetrical but has a long tail on one or other side of the graph.
spatial distribution
variations in distribution related to position in space, e.g. close to the door of a barn.
see t-test.
temporal distribution
variation in distribution related to time, e.g. occurrence of disease incidents after visits by veterinarians, inseminators, feed salesmen.


1. the number of occurrences of a periodic process in a unit of time.
2. in statistics, the number of occurrences of a determinable entity per unit of time or of population.

cumulative frequency
the graph of its cumulative frequencies.
frequency distribution
see frequency distribution.
expected frequency
the expected number of occurrences.
observed frequency
the actual frequency; as opposed to the expected frequency.
relative frequency
the number of observations of a particular, nominated value expressed usually as a proportion of the total frequency.
total frequency
the total number of observations in the set of data.
ultrasound frequency
References in periodicals archive ?
In this case it would seem the frequency distribution for the orbit positions cannot be built because the function has only one variable argument [v.
Frequency distributions of the frequency use of conference proceedings for teaching and research roles are presented in Table 5.
More data will likely reduce the confidence intervals for the frequencies of each incubation day (Figure 1), giving a clearer picture of the actual frequency distribution of all incubation periods.
The probability of low-abundance PSA mRNA transcripts was assessed with use of the Poisson distribution, which revealed the expected frequency distribution of positive PCR tests.
Frequency Distribution (Grouped and Cumulative) of Income Valid Cumulative Frequency Percentage Percentage Percentage Valid <$10,000 4 12.
Frequency distributions are analytical tools which provide the basis for media plan comparisons.
The time-at-depth frequency distribution showed that the loggerhead sea turtles spent about 40% of their time in the top meter and virtually all their time shallower than 100 m (Fig.
Once the predicted frequency distribution is available for a joist (or several joists assumed to share load), some meaningful measures of floor performance were required for the purpose of comparing VSR and MSR type joists.
We have found that the one-percentile tails of the Hb frequency distributions are located above the specification limits in most cases.
In this edition, more problems, a discussion of data and frequency distributions, and an appendix on the structure of data sets and the use of computers have been added.

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