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  2. Covariance matrix - Wikipedia

    en.wikipedia.org/wiki/Covariance_matrix

    Throughout this article, boldfaced unsubscripted and are used to refer to random vectors, and Roman subscripted and are used to refer to scalar random variables.. If the entries in the column vector = (,, …,) are random variables, each with finite variance and expected value, then the covariance matrix is the matrix whose (,) entry is the covariance [1]: 177 ...

  3. Estimation of covariance matrices - Wikipedia

    en.wikipedia.org/wiki/Estimation_of_covariance...

    The sample covariance matrix (SCM) is an unbiased and efficient estimator of the covariance matrix if the space of covariance matrices is viewed as an extrinsic convex cone in R p×p; however, measured using the intrinsic geometry of positive-definite matrices, the SCM is a biased and inefficient estimator. [1]

  4. Life-cycle cost analysis - Wikipedia

    en.wikipedia.org/wiki/Life-cycle_cost_analysis

    Life-cycle cost analysis (LCCA) is an economic analysis tool to determine the most cost-effective option to purchase, run, sustain or dispose of an object or process. The method is popular in helping managers determine economic sustainability by figuring out the life cycle of a product or process.

  5. Life-cycle assessment - Wikipedia

    en.wikipedia.org/wiki/Life-cycle_assessment

    Life cycle inventory (LCI) analysis involves creating an inventory of flows from and to nature (ecosphere) for a product system. [32] It is the process of quantifying raw material and energy requirements, atmospheric emissions, land emissions, water emissions, resource uses, and other releases over the life cycle of a product or process. [33]

  6. Covariance and correlation - Wikipedia

    en.wikipedia.org/wiki/Covariance_and_correlation

    With any number of random variables in excess of 1, the variables can be stacked into a random vector whose i th element is the i th random variable. Then the variances and covariances can be placed in a covariance matrix, in which the (i, j) element is the covariance between the i th random variable and the j th one.

  7. Partial least squares regression - Wikipedia

    en.wikipedia.org/wiki/Partial_least_squares...

    Partial least squares (PLS) regression is a statistical method that bears some relation to principal components regression and is a reduced rank regression [1]; instead of finding hyperplanes of maximum variance between the response and independent variables, it finds a linear regression model by projecting the predicted variables and the observable variables to a new space of maximum ...

  8. Product life-cycle theory - Wikipedia

    en.wikipedia.org/wiki/Product_life-cycle_theory

    The Product Life Cycle Theory is an economic theory that was developed by Raymond Vernon in response to the failure of the Heckscher–Ohlin model to explain the observed pattern of international trade. The theory suggests that early in a product's life-cycle all the parts and labor associated with that product come from the area where it was ...

  9. Covariance - Wikipedia

    en.wikipedia.org/wiki/Covariance

    In probability theory and statistics, covariance is a measure of the joint variability of two random variables. [1] The sign of the covariance, therefore, shows the tendency in the linear relationship between the variables.