normal distribution



  • noun a graph of distribution which is symmetrical around a mean. It is shaped like a bell.


  • For a random variable, a probability distribution which is symmetrical about the mean value, and which continuously diminishes in value until reaching zero at each extreme. It is utilized to determine the probability of the value of the variable falling within a given interval of values, and when graphed has the shape of a symmetrical bell. Various phenomena, such as some natural frequencies, have a normal distribution. Also called bell-shaped distribution, or Gaussian distribution.

Health Economics

  • (written as Normal Distribution)
    A frequency distribution with one mode, having the symmetrical shape of a bell. It is characterized by two parameters: the mean and the standard deviation. Sixty-seven per cent of values lie within one standard deviation on either side of the mean.
  • synonymGaussian distribution
    (written as Normal Distribution)
  • synonymGaussian Distribution

Information & Library Science

  • noun a statistical term indicating that the majority of results will appear towards the centre of a graph with smaller amounts towards the top and bottom


  • noun a term used in sampling theory, referring to the results of a sample and meaning a symmetrical distribution of values around a mean or average, so that you can be confident that the sample is properly representative of the people being surveyed in a study