Main content
Course: Algebra 2 (Eureka Math/EngageNY) > Unit 4
Lesson 7: Topic C: Lesson 12: Types of statistical studiesObservational studies and experiments
Google ClassroomWe do studies to gather information and draw conclusions. The type of conclusion we draw depends on the study method used:
- In an observational study, we measure or survey members of a sample without trying to affect them.
- In a controlled experiment, we assign people or things to groups and apply some treatment to one of the groups, while the other group does not receive the treatment.
Problem 1: Drinking tea before bedtime
A study took random sample of adults and asked them about their bedtime habits. The data showed that people who drank a cup of tea before bedtime were more likely to go to sleep earlier than those who didn't drink tea.
Another study took a group of adults and randomly divided them into two groups. One group was told to drink tea every night for a week, while the other group was told not to drink tea that week. Researchers then compared when each group fell asleep.
Problem 2: Social media and happiness
A study randomly assigned volunteers to one of two groups:
- One group was directed to use social media sites as they usually do.
- One group was blocked from social media sites.
The researchers looked at which group tended to be happier.
Another study took a random sample of people and examined their social media habits. Each person was classified as either a light, moderate, or heavy social media user. The researchers looked at which groups tended to be happier.