Is the correlation more father --> son than father -->daughter? Is there a mean effect between parents? Which sex is the most dominant in passing along this trait? Are there any instances of the child having a greater than the average or either parent? That would be very interesting data.
Are there any instances of the child having a greater than the average or either parent?
There are many such instances. And there are instances of children having lower IQ scores than either parent.
More important, it is a rare case when the same individual has the same IQ score over the course of life. IQ can change over the course of life quite a lot. And any two brands of IQ test will not agree entirely in how they sort a group of test-takers into a rank order. And IQ scores don't tell the whole story about all the meaningful mental abilities that a learner has, as Lewis Terman (the first developer of IQ tests in the United States) was very honest about pointing out:
"There are, however, certain characteristics of age scores with which the reader should be familiar. For one thing, it is necessary to bear in mind that the true mental age as we have used it refers to the mental age on a particular intelligence test. A subject's mental age in this sense may not coincide with the age score he would make in tests of musical ability, mechanical ability, social adjustment, etc. A subject has, strictly speaking, a number of mental ages; we are here concerned only with that which depends on the abilities tested by the new Stanford-Binet scales."
Comments
Is the correlation more father --> son than father -->daughter? Is there a mean effect between parents? Which sex is the most dominant in passing along this trait? Are there any instances of the child having a greater than the average or either parent? That would be very interesting data.
Are there any instances of the child having a greater than the average or either parent?
There are many such instances. And there are instances of children having lower IQ scores than either parent.
More important, it is a rare case when the same individual has the same IQ score over the course of life. IQ can change over the course of life quite a lot. And any two brands of IQ test will not agree entirely in how they sort a group of test-takers into a rank order. And IQ scores don't tell the whole story about all the meaningful mental abilities that a learner has, as Lewis Terman (the first developer of IQ tests in the United States) was very honest about pointing out:
"There are, however, certain characteristics of age scores with which the reader should be familiar. For one thing, it is necessary to bear in mind that the true mental age as we have used it refers to the mental age on a particular intelligence test. A subject's mental age in this sense may not coincide with the age score he would make in tests of musical ability, mechanical ability, social adjustment, etc. A subject has, strictly speaking, a number of mental ages; we are here concerned only with that which depends on the abilities tested by the new Stanford-Binet scales."
(Terman & Merrill 1937, p. 25)