path diagram

a figure describing the hypothesized relations tested in an analysis of simultaneous linear relationships among measured or manifest variables; the object is to identify the causal relationships or logical ordering among variables. Each measured variable is designated by a box, and latent variables are represented by ovals. Covariances or correlations between exogenous variables and between errors are represented by curved lines with arrowheads at both ends. Paths are represented by straight lines with an arrowhead pointing from the independent variable toward the dependent variable. Associated with each path is either an asterisk or a number. The asterisks indicate free parameters, whose values will be estimated from the data, whereas the numbers indicate fixed parameters, whose values do not change as a function of the data. Also called path model. See also path analysis.

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Psychology term of the day

November 17th 2024

REM sleep

rapid-eye-movement sleep: the stage of sleep, formerly called desynchronized sleep, in which most dreaming tends to occur during which electroencephalograms show activity that resembles wakefulness (hence, it is also known as paradoxical sleep) except for inhibition of most skeletal and cranial muscles. This stage has two phases—tonic and phasic—and it is largely during the phasic period that muscle twitches and bursts of rapid eye movements occur. REM sleep accounts for one quarter to one fifth of total sleep time. Compare NREM sleep.