Answer:
Biased or non representative sample.
Step-by-step explanation:
Biased sample may be defined as the collected sample in which the selected population has the lower sampling probability than the other sample. The individuals are not equally selected in the bias sample.
Professor Jones had only tested the children of college professors. This limited group shows the biased or non representative sample. The environmental experiences and genetic inheritance. The faculty children can differ from general population in important different ways that could influence the rate of the language development.
Thus, the answer is biased or non representative sample.