6. A developmental psychologist believes that language learning in preschool girls differs from boys. For example, girls are more likely to use more complex sentences structures earlier than boys. The researcher believes that a second factor affecting language skills is the presence of older siblings; that is, preschool children with older siblings will generate more complex speech than older children. The researcher carefully records the speech of a classroom of 40 preschool children (20 females, 20 males), half of whom have older siblings. The speech of each child is then given a complexity score. a. Which method of analysis should the researcher use? Explain. b. Make of diagram of this design