A technique which requires a supervisor to designate a fixed number of workers in each of several performance categories is a(n)

Jenny's son received his mumps, measles, and rubella vaccine approximately six months ago

Shortly after his 2nd birthday, she noticed that he is showing many of the classic signs of autism. Her belief that the vaccine caused his autism is A) an example of confirmation bias. B) an example of hindsight bias. C) an example of illusory correlation. D) supported by several scientific studies.

Olly lives in Spain. Like other children in Europe, he is more likely to have:

a. one sibling b. two siblings c. three siblings d. no siblings