Experiment Sample Survey Observational

To test the effects of eating breakfast on test grades. I randomly select half of my students and feed them breakfast while giving the other half nothing to eat. I then give them all a test and compare the test grades of each group.

Is this an experiment or an observational study?

• Experiment

• Observational study

• Neither

• Both experiment and observational study.

The conductor has control over the environment in this setting

• experiment

• observational study

• population

• sample

a controlled study in which the researcher attempts to understand cause-and-effect relationships by assigning subjects to groups and deciding which treatments each group receives

• survey

• observational study

• experiment

You want to find out if people who eat a candy bar immediately before a math test get higher scores than people who do not.

• survey

• observational study

• experiment

A study where researchers deliberately impose treatment on the individuals.

• Experiment

• Observational Study

• Survey

• Census

Which scenario is best described as an observational study?

• For a class project, students in Health class ask every 10^th student entering the school if they eat breakfast in the morning

• A social researcher wants to learn whether or not there is a link between attendance and grades. She gathers data from 15 school districts

• A researcher wants to learn whether or not there is a link between children’s daily amount of physical activity and their overall energy level. During lunch at the local high school, she distributed a short questionnaire to students in the cafeteria

• Sixty seniors taking a course in Advanced Algebra Concepts are randomly divided into two classes. One class uses a graphing calculator all the time, and the other class never uses graphing calculators. A guidance counselor wants to determine whether there is a link between graphing calculator use and students’ final exam grades

Determining if students using a calculator on a math final exam score better than students who do not use a calculator 

• Cenus

• Sample Survey

• Experiment

• Observational Study

A random selection of people are called every morning for a week to determine if television shows are too violent. 

• Census

• Sample Survey

• Experiment

• Observational Study

Estimate the number of students in your school who play video games more than 10 hours per week.

• Census

• Sample Survey

• Experiment

• Observational Study

In a certain school, students can choose whether to eat in the school’s cafeteria. A reporter working for the school’s newspaper polled students on their reactions to changes in the menu at the cafeteria. For each student leaving the cafeteria in one 20-minute time period, the reporter used a die to determine whether to stop the student and ask how he or she felt about the new menu. In the reporter’s article it was stated that a random sample of the students showed that 23% of the school’s student population was happy with the new menu. Which of the following statements is true?

• Because each student leaving the cafeteria was randomly selected and could choose to answer or not, this is a random sample of the student population, and the 23% is an accurate measurement of the school population’s view of the new menu.

• Because students self-selected whether to eat in the cafeteria, the sampling method might be biased and the sample might not be representative of all students in the school.

• The survey would have been more effective if the reporter had collected the data in one 10-minute time period rather than in one 20-minute time period.

• The survey would have been more effective if students who cared about the food could have called the reporter to tell how they felt about the new menu, so that only students with opinions on the subject would have been surveyed.

• Because no treatment was imposed on the students eating in the cafeteria, one cannot make any conclusions about the new menu.