# Vital Statistic

Time Series – A set of observations (data that are classified according to a unit of time. For example: monthly sales. See also: Time series Analysis

Time Series Analysis – Techniques that are employed in an attempt to comprehend alterations in time series. This may result in an improvement of predictive techniques. See also: Time Series

Trichotomy – Classification into three parts, three classes: “yes/no/don’t know;” expensive/cheap/ right price.”

Two-by-two Frequency Table – A tabular representation of data that occur in a double dichotomy. For example: each sample element is A or not-A and contains X or not -X.  See also: Double dichotomy/Table

Vital Statistics – The gathering, analysis and interpretation of numerical data pertaining to people, specifically figures for birth and death.

Asymmetrical Distribution – A distribution in which no central value exists. Expressed as a formula this means that: f(x-a)=f(a-x)  f(x) is the frequency function.

Bernoulli Distribution – Syn: Binomial Distribution   See: Binomial Distribution

Bimodal – A frequency distribution with two modes. The bimodal distribution in a graph has two peaks. For example: the birth figures since 1900 indicate that there have been two birth peaks following both of the world wars. See also: Unimodal/Frequency distribution/Mode

Binomial Distribution – Syn: Bernoulli Distribution   A probability distribution. The probability (P) that ® appears in (N) independent trials is:    (N/R)Q-RpR, where Q=I-P    In this distribution of probability something is either P or not-P. There are no other possibilities. For example: head or tails, pregnant or not.    See also: Hypothetical population/Trial/Probability Distribution

Bivariate Distribution – A distribution consisting of two variables, either composed as such or coincidental.

Categorical Distribution – The classification of data into categories according to a qualitative description and not according to a numerical variable. For example: sex (male/female)    See also: Category

Frequency Distribution – involves the collection of data from a large group (individuals, objects) followed by the classification f these data in sequence. The purpose of the frequency distribution is to render a large amount of data accessible and comprehensible. For example: in a sample, 70 persons own 5 radios, 90 own 4, 200 own 3,400 own 2, and 50 persons each own 1 radio. When such a distribution is expressed in table form, it is termed a frequency table.   See also: Histogram/Table?Frequency?Frequency table

J-shaped Distribution – An extreme form of asymmetrical frequency distribution. The highest frequency occurs at the beginning (or end) of the frequency group, and a decreasing or increasing frequency is found elsewhere. The shape of this distribution corresponds, approximately, to the letter “J” or an inverted “J”. A frequency distribution of traffic accidents is J-shaped. By far the greatest number of victims are young.    See also; Skewed distribution/Asymmetrical Distribution

Multivariate Distribution – The simultaneous distribution of a number of P variables (P<1) or equivalent; the probability of P variables.

Non-parametric Statistics – Form of statistics that makes no assumptions concerning population distribution or concerning any constant in the population.  See also: Parameter

Norm Setting – Establishing terms of reference to which subsequent data or decisions can be compared. For example, in a large-scale survey, the percentage of TV viewers who are able to recall a particular commercial is determined. That percentage is taken as the norm. In later small-scale surveys, the extent to which certain commercials are remembered is compared to the original figure.   See also: Norm

Normal – 1. According with a certain norm

1. Falling within a certain category, e.g., if 99% of the population has a telephone, then the remaining 1% is not normal.