Monthly Archives: August 2014

Error Correction Model in Time Series Regression

A strong assumption of time series regression, a widely used technique in econometrics, is the stationarity. It requires that the variables entered in the regression have their variances (standard deviations), covariances (auto-correlations), and means, that are independent of time. A … Continue reading

Posted in Stats | Tagged

Studies of IQ heritability among Chimpanzees

IQ heritability among humans is well-known state of research. Much less has been done on chimpanzees. Hopkins et al. (2014) published a recent study that touches the subject. 99 chimpanzees, aged 9 to 54 (mean = 24.55, SD = 10.67), … Continue reading

Posted in Behavioral Genetics | Tagged

Racial differences in the long-term trend NAEP scores (1975/78-2012)

I analyze the LTT NAEP achievement scores, a public data set available at NCES. In general, minority-majority ethnic groups show a secular decline in d gap, for both math and reading tests, and this occurs at all ages of assessment … Continue reading

Posted in IQ Survey & Analysis | Tagged