4. New research supports the idea that people who get a good night's sleep are better at recognizing facial expressions. A sample of 18 healthy young adult volunteers were exposed to 70 images of facial expressions, ranging from friendly to threatening. They were each shown images both after a full night of sleep and after sleep deprivation (being kept awake for 24 hours), and whether each individual got a full night of sleep or was kept awake first was randomly determined. The study found that people were much worse at recognizing facial expressions after they had been kept awake. a. Identify the cases in this study: b. Identify the explanatory and response variables, indicating which one is each, and whether the variable is categorical or quantitative. The explanatory variable (variable name or description) (categorical/quantitative) The response variable (variable name or description) (categorical/quantitative) c. This is a matched pairs experiment, because the same subjects received both treatments. In order to conclude a cause and effect relationship between the variables for this matched pairs experiment, what would we need to verify about the treatment assignment