You want to survey 20 of the 150 ninth graders to get their opinion on the school’s new schedule. Which of these methods is most likely to lead to a sample that is the most representative of the 150 ninth graders?

The United States Senate has 2 senators from each of the 50 states. Select all methods that would select a sample of 10 senators at random from the entire Senate.

Jada is designing a study to determine whether mold grows faster in tap water or bottled water. To do this she compares the growth rate of mold growing in a glass of tap water to the growth rate of mold growing in a glass of bottled water. 

1. What type of study is Jada designing?
2. How could her design be improved to collect data that would be better for answering the question of interest?

What type of study would you conduct if you wanted to know how many miles per week, on average, students on the school's cross country team run during the summer? Explain your reasoning.

Describe the design of an experimental study that could determine whether exercising improves the speed at which students type a text message.