focusing mechanism

the system of ciliary muscles, lens elasticity, and ocular-fluid pressure that enables the eye to focus an image sharply on the retina. The natural shape of the lens is spherical, which is required to focus near objects. When focusing distant objects, the lens is flattened by tension exerted on the zonules as the ciliary muscles are relaxed and by fluid pressure within the eye.

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Psychology term of the day

November 24th 2024

regression sum of squares

(symbol: SS_regression) a number indicating the amount of variance in a dependent variable that can be explained by the variance in one or more associated independent variables. It thus describes how well a particular model fits the observed data. For example, in linear regression it is used to calculate a coefficient of determination or a coefficient of multiple determination, and in analysis of variance it is used to determine the total sum of squares and calculate an F ratio. Compare error sum of squares.