For the two studies described, answer each question below:
1. You want to design a study to determine the effects of age on the quantity of social interaction. You will measure how many friends each of my participants report they speak to on a given day. You will use three groups of participants: 8-10-year-olds, 12-15-year-olds, and 17-20-year-olds. Thirty participants will be recruited from each age group.
a) What type of developmental design is this? Explain your answer.
b) Is this an experiment? Why or why not?
c) List one possible covariate that I might use in this study to remove a source of bias that might exist in my data. Explain why you think this measure will increase the power to detect an age difference in my data analysis.
2. You want to conduct an experiment to determine the effect of running on verbal ability. You ask participants to run 1 mile and then speak all the words they can in a 30-second period.
a) List two possible sources of bias you should consider controlling for in this study and how you might control for them in your design.