Shelly's Study Compared the Effects of Two Different Types of Phonemic

Multiple Choice

Shelly's study compared the effects of two different types of phonemic instruction on young children who volunteered to participate in the study. She gave each participant who completed the study two pencils and three stickers. These incentives are likely a strategy to decrease the threat of

A) history.
B) instrumentation.
C) differential selection.
D) mortality.