When performance tests, rather than verbal tests, are used,
◦ the IQ scores of those who are deaf are lower than those who are hearing.
◦ there is no difference in IQ scores between those who are deaf and those who are hearing.
◦ the IQ scores of both those who are hearing and those who are deaf are lower.
◦ the IQ scores of those who are deaf are higher than those who are hearing.