Figure 7. Change in average science scores of 8th-grade
students, by education system: 20072011 and 19952011 Score is
higher than U.S. score. Score is lower than U.S. score. Change
from 2007 to 2011. Change from 1995 to 2011. # Rounds to zero.
*p<.05. Change in average scores is significant. 1 The change in
average score is calculated by subtracting the 2007 or 1995
estimate, respectively, from the 2011 estimate using unrounded
numbers. 2 National Defined Population covers 90 to 95 percent
of National Target Population for 2011 (see appendix A). 3
Nearly satisfied guidelines for sample participation rates after
replacement schools were included for 2011. 4 National Target
Population does not include all of the International Target
Population for 2011 (see appendix A). 5 Exclusion rates for
Georgia are slightly underestimated as some conflict zones were
not covered and no official statistics were available for 2011.
6 The TIMSS International Study Center has reservations about
the reliability of the average ac