normal distribution - definition of normal distribution in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia.

distribution /dis·tri·bu·tion/ (dis″trĭ-bu´shun)

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.

chi-square distribution a distribution of sample differences using observations of a random sample drawn from a normal population.

normal distribution a continuous probability density function roughly characterizing a random variable that is the sum of a large number of independent random events; usually represented by a smooth bell-shaped curve symmetric about the mean.

Normal distribution. The approximate percentage of the area (or frequency) lying under the curve between standard deviations is indicated.

normal distribution,

(in statistics) a theoretic distribution frequency of variable data usually represented graphically by a bell-shaped curve that reaches a peak about the mean.

normal distribution,

n a curve representing the frequency with which the values of a variable are obtained or observed when the number is infinite and variation is subject only to chance factors. The curve is a symmetrical, bell-shaped curve with the highest frequency occurring in the middle and gradually tapering toward the extremes. In a normal distribution, 68.2% of all scores cluster around the mean within approximately 1 standard deviation, 95.4% within approximately 2 standard deviations, and 99.7% within approximately 3 standard deviations. Also called
normal curve, Gauss' curve.

distribution

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

see 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.

t-distribution

see t-test.

temporal distribution

variation in distribution related to time, e.g. occurrence of disease incidents after visits by veterinarians, inseminators, feed salesmen.

normal

1. agreeing with the regular and established type. When said of a solution, it denotes one containing one chemical equivalent of solute per liter of solution; e.g. a 0.5 normal (0.5 N) solution has a concentration of 0.5 Eq/l. The use of standard units (Eq/l) is now generally preferred in pharmacy and clinical medicine although elsewhere molarity (M) is used.

2. in the context of infectious diseases, not immunized or infected.

3. statistically speaking, the values of a variable which follow a bell-shaped or Gaussian distribution.

normal distribution

see normal distribution.

normal limits

limits of the classification of 'normal' in the results of a test.

normal saline

contains 0.9% sodium chloride. Called also isotonic saline.