A. This is an inference based on factor analytic research by numerous researchers.
B. This is an inference based on theoretical construct and reported research results.
C. This is an assumption. This information about Gardner’s theory is not supported by research.
D. This is an observation. Data are provided in Figure 6.3.
E. This is an observation. The section, “Do Changes in Intelligence Vary?” presents numerous investigations and research data to support individual differences in intellectual change.