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stem-and-leaf plot

Overview page. Subjects: Mathematics — Psychology.

A method of displaying grouped data, by listing the observations in each group, resulting in something like a histogram on its side. For the observations 45, 25, 67, 49, 12, 9, 45, 34, 37,...

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Tower of Hanoi

Overview page. Subjects: Mathematics — Psychology.

A logical puzzle, frequently studied in cognitive psychology and used as a test of problem-solving ability, consisting of three pegs, on one of which are placed a number of discs of varying...

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travelling salesman problem

Overview page. Subjects: Mathematics — Psychology.

A network problem that can be formulated as a combinatorial optimization problem. A salesman has to visit a number of interconnected destinations. The problem is to determine the route that...

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trimmed mean

Overview page. Subjects: Probability and Statistics — Psychology.

In statistics, the arithmetic mean calculated after eliminating a specified proportion or percentage of the largest and smallest scores, a common type being the 5 per cent trim. It is used...

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Ward's method

Overview page. Subjects: Psychology — Probability and Statistics.

An agglomerative clustering method proposed by Ward in 1963. The clustering criterion is based on the error sum of squares, *E*, which is defined as the sum of the squared distances of...

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z test

Overview page. Subjects: Psychology — Probability and Statistics.

A test, using a sample of *n* independent observations, of the null hypothesis that a normal distribution with variance *σ*
^{2}, has mean *μ*. Writing the sample mean as *x̄*, the test...