4.1.8 Qulz: Using Data to Make Inferences Queation 7 of 10 Which option is an example of a survey? A. Testing the effectiveness of a mouthwash by allowing one group to use in and comparing the results with those of a group that doesn't use it B. Finding the number of red jellybeans in an average jar of jellybeans by counting C. Placing different groups of people in different colored rooms and recording their mood D. Having customers fill out a questionnaire about their favorite brand of toothpaste

The correct answer is: **D. Having customers fill out a questionnaire about their favorite brand of toothpaste** **Explanation:** A **survey** involves collecting data from individuals, typically through questionnaires or interviews, to gather information about their opinions, preferences, or behaviors. - **Option A** describes an **experiment** where the effectiveness of mouthwash is being tested between two groups. - **Option B** involves **data collection through counting**, which is more of a direct measurement rather than a survey. - **Option C** also describes an **experimental setup** aimed at observing the effect of room color on mood. - **Option D** clearly involves **collecting data from customers** about their preferences, fitting the definition of a survey. Therefore, **Option D** is the best example of a survey. **Answer:** D. Having customers fill out a questionnaire about their favorite brand of toothpaste