2. A nutritionist wants to collect data on how much caffeine the average American drinks per day. She has the following ideas for how she could obtain a sample:
a. Ask the first 20 adults who arrive at a grocery store after 10:00 a.m. about the average amount of caffeine they consume each day.
b. Every 30 minutes, ask the first adult who comes into a coffee shop about the average amount of caffeine they consume each day.​