SOLVED

220)The average IQ score for each age group is arbitrarily set at 100. 221)By definition, two-thirds of all IQ test takers score precisely at 100. 222)The distribution of IQ scores approximates a bell-shaped curve. 223)Very high or very low IQ scores are rare. 224)The kind of intelligence that produces high IQ scores is highly heritable. 225)It is clear that the kind of intelligence that produces high IQ scores is only weakly heritable. 226)Behavioural-genetic studies have shown that as adopted children grow into adulthood, the correlation between their IQ scores and those of their biologically unrelated family members diminishes to zero. 227)Behavioural-genetic studies have shown that as adopted children grow into adulthood, the correlation between their IQ scores and those of their biologically unrelated family members is about 0.45. 228)For children and adolescents, heritability estimates average around 0.50; that is, about half of the variance in IQ scores is explainable by genetic differences. 229)For children and adolescents, heritability estimates average around 0.75; that is, about three-quarters of the variance in IQ scores is explainable by genetic differences.