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  2. Contrast (statistics) - Wikipedia

    en.wikipedia.org/wiki/Contrast_(statistics)

    A contrast is defined as the sum of each group mean multiplied by a coefficient for each group (i.e., a signed number, c j). [10] In equation form, = ¯ + ¯ + + ¯ ¯, where L is the weighted sum of group means, the c j coefficients represent the assigned weights of the means (these must sum to 0 for orthogonal contrasts), and ¯ j represents the group means. [8]

  3. Design of experiments - Wikipedia

    en.wikipedia.org/wiki/Design_of_experiments

    Example of orthogonal factorial design Orthogonality concerns the forms of comparison (contrasts) that can be legitimately and efficiently carried out. Contrasts can be represented by vectors and sets of orthogonal contrasts are uncorrelated and independently distributed if the data are normal.

  4. 1951 USAF resolution test chart - Wikipedia

    en.wikipedia.org/.../1951_USAF_resolution_test_chart

    A 1951 USAF resolution test chart is a microscopic optical resolution test device originally defined by the U.S. Air Force MIL-STD-150A standard of 1951. The design provides numerous small target shapes exhibiting a stepped assortment of precise spatial frequency specimens.

  5. Moderation (statistics) - Wikipedia

    en.wikipedia.org/wiki/Moderation_(statistics)

    Effects coding is used when there is no reference group or orthogonal contrasts. The intercept b 0 {\displaystyle b_{0}} [ cleanup needed ] is the grand mean (the mean of all the conditions). The regression coefficient b A = Y ¯ A − Y ¯ 1 … n ¯ {\displaystyle b_{A}={\bar {Y}}_{A}-{\overline {{\bar {Y}}_{1\dots n}}}} is the difference ...

  6. Categorical variable - Wikipedia

    en.wikipedia.org/wiki/Categorical_variable

    Categorical data is the statistical data type consisting of categorical variables or of data that has been converted into that form, for example as grouped data. More specifically, categorical data may derive from observations made of qualitative data that are summarised as counts or cross tabulations , or from observations of quantitative data ...

  7. Grid plan - Wikipedia

    en.wikipedia.org/wiki/Grid_plan

    Traditional orthogonal grid patterns generally have greater street frequencies than discontinuous patterns. For example, Portland's block is 200 feet × 200 feet while Miletus' is half that size and Timgad's half again (see diagram). Houston, Sacramento and Barcelona are progressively bigger reaching up to four times the area of Portland's block.

  8. In-phase and quadrature components - Wikipedia

    en.wikipedia.org/wiki/In-phase_and_quadrature...

    So the phase difference is attributed to the current function, e.g. sin(2 π ft + φ), whose orthogonal components are sin(2 π ft) cos(φ) and sin(2 π ft + π /2) sin(φ), as we have seen. When φ happens to be such that the in-phase component is zero, the current and voltage sinusoids are said to be in quadrature , which means they are ...

  9. Factorial experiment - Wikipedia

    en.wikipedia.org/wiki/Factorial_experiment

    In the tables in the following examples, the entries in the "cell" column are treatment combinations: The first component of each combination is the level of factor A, the second for factor B, and the third (in the 2 × 2 × 2 example) the level of factor C. The entries in each of the other columns sum to 0, so that each column is a contrast ...