Related article: where N is the sample size, X is the sample mean, ? is the standard deviation, and the subscripts a and b denote each group. When the black-white difference for a specific test is reported subsequently in the text, this equation has been used to compute it. 34 The Long Term Trend Study with consistent data for the NAEP from the early 1970's through 2004 is now available in mathematics and reading for students tested at ages nine, thirteen, and seventeen. 35 For nine-year-olds, the gap in reading scores expressed as points was smaller in 2004 (26 points) than in 1988 (29 points), but the difference in standard deviations was fractionally larger (.76 standard deviations in 2004 as compared with .74 in 1988). 36 Hedges Atacand 8mg Tablets and Nowell (1998): 154. 37 I will venture a prediction that a variety of academic achievement measures in elementary and secondary school will soon show renewed convergence because of the No Child Left Behind Act, which puts schools under intense pressure to teach to the test in basic skills. If students are drilled on limited ranges of subject matter, scores will tend to rise. The more basic the tests Atacand 16 Mg Price are (that is, the easier they are), the more that improvements among the least skilled will affect the mean. Also, the higher the stakes facing a school-and the No Child Left Behind Act makes those stakes very high indeed-the greater will be the incentives for administrators to use some of the many resources at their disposal to make the results come out right, through the judicious manipulation of suspensions and absences, and through outright cheating (yes, it has been known to happen). Some convergence in black and white test scores will probably occur, but partitioning that effect among the competing explanations is a task that will take a few years. Insofar as the convergence has been the result of teaching to the test and of artifacts, it will be temporary. 38 In a given year, IQ Buy Atacand Hctz tests and academic tests administered to the same sample will produce similar results. Thus, it is possible to make a reasonably good guess about a person's IQ based on his SAT score compared to the distribution of SAT scores in a given year, and after taking the composition of the SAT population into account. But the results of academic tests are sensitive to changes in academic achievement, whereas IQ tests are explicitly designed to measure a general mental factor, g, that is independent of academic achievement. A notorious illustration of the way that academic test scores can drop is the period during the 1960's and 1970's when SAT scores declined substantially, even after accounting for changes in the pool of test-takers (Murray and Herrnstein 1992). The intelligence of American youth was not declining, just their academic achievement. 39 The significance of g-loadings is discussed later in the text. In terms of interpreting trends over time, the problem is that tests are not equally good measures of g. They go from poor (e.g., a basic reading test) to excellent (the Atacand 60 Mg most highly g-loaded, individually administered IQ test). It is as if you were trying to measure changes in average height with measuring tapes of varying accuracy. For a statement of the no-change position, see Gottfredson (2005a), or a summary of her argument in Gottfredson (2005b). 40 The .97 figure comes from my analysis of the proxy AFQT score in the most recent release of the 1997 cohort of the National Longitudinal Study of Youth (NLSY). I call it a proxy score because, eight years after the test battery was administered, the Armed Forces still has not gotten around to creating an official AFQT score. The version created by the NLSY staff is a composite of the same subtests used for previous versions of the AFQT, and takes the subject's age into account. The NLSY has released the percentile scores, which I converted to standard scores. The analysis used the NLSY's sample weights to make the results representative of the national population. The NLSY data can be downloaded online. 41 I take the 1.10 figure from Roth, Bevier, Bobko et al. (2001), a meta-analysis of the black-white difference in both achievement tests and IQ tests. The Roth et al. results are necessarily reflective of pencil-and-paper tests, because that is where the overwhelming