l22 - Measurement Error Example (Supplemental) Here we give...

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Measurement Error Example (Supplemental)—Page 1 Measurement Error Example (Supplemental) Here we give a hypothetical example that illustrates the properties shown in the measurement handout. We create a data set where the true measures (Yt and Xt) have a correlation of .7 with each other – but the observed measures (Y and X) both have some degree of random measurement error, and the reliability of both is .64. The way I am constructing the data set, using the corr2data command, there will be no sampling variability, i.e. we can act as though we have the entire population. . matrix input corr = (1,.7,0,0\.7 ,1,0,0\0,0,1,0\0,0,0,1) . matrix input sd = (4,8,3,6) . matrix input mean = (10,7,0,0) . corr2data Yt Xt ey ex, corr(corr) sd(sd) mean(mean) n(500) (obs 500) . * Create flawed measures with random measurement error . gen Y = Yt + ey . gen X = Xt + ex A & B. We see that the flawed, observed measures have the same means as the true measures – but their variances & standard deviations are larger: . sum Yt Y Xt X Variable | Obs Mean Std. Dev. Min Max -------------+-------------------------------------------------------- Yt | 500 10 4 -2.639851 22.83863 Y | 500 10 5 -3.706503 26.55569 Xt | 500 7 8 -16.16331 28.80884 X | 500
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This note was uploaded on 02/29/2012 for the course SOC 63993 taught by Professor Richardwilliams during the Spring '11 term at Notre Dame.

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l22 - Measurement Error Example (Supplemental) Here we give...

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