Experimental vs Observational

Four groups of randomly selected people are assigned a different diet. After six months, the blood pressures of each group are compared.

• Observational Study

• Experiment

Rats with cancer are divided into two groups. One group receives 5 milligrams of a medication that is thought to fight cancer and the other receives 10 mg. After 2 years, the spread of cancer is measured.

• Observational Study

• Experiment

A researcher stood at a school parking lot entrance to see if the color of a car is related to the driver not wearing a seatbelt.

• Observational Study

• Experiment

You want to see if students who have a 4.0 grade point average study more than those who do not.

• experiment

• observational study

In an ________________, a researcher observes and measures characteristics of interest of part of the population but does not change existing conditions.

• Experiment

• Observational Study

Can pleasant aromas help a student learn better? Two researchers believed that the presence of a floral scent could improve a person’s learning ability in certain situations. They had 22 people work through a pencil-and-paper maze six times, three times while wearing a floral-scented mask and three times wearing an unscented mask. The three trials for each mask closely followed one another. Testers measured the length of time it took subjects to complete each of the six trials. They reported that, on average, subjects wearing the floral-scented mask completed the maze more quickly than those wearing the unscented mask, although the difference was not statistically significant. This study is

• a convenience sample 

• an observational study, not an experiment

• an experiment, but not a double-blind experiment 

• a double-blind experiment

210 college students were randomly assigned to play either a violent or nonviolent video game.  A short time later, the students were presented with the opportunity to trivially harm another person and results comparing the two groups were recorded.
Is this study or ? 

• Observational

• Experimental

A study is conducted to investigate the relationship between owning pets and happiness. 100 subjects are randomly selected and data on whether or not a pet is owned and a happiness score (1‐10, 10 being extremely happy) are obtained.
Is this an OBSERVATIONAL or EXPERIMENTAL study?

• Observational

• Experimental

Researchers select 150 high school students and randomly divide them into two groups: the first group and the control group. Intervention: The second group uses a gamified learning platform for the subject material, where lessons are delivered through interactive games and quizzes. The control group receives traditional instruction without any gamification elements. Duration: Both groups participate in their respective instructional methods over a period of eight weeks. Assessment: At the end of the eight weeks, both groups take the same standardized test covering the same material. Data Analysis: Researchers compare the test scores between the two groups to determine if the gamified approach led to significantly higher scores than the traditional method.

• The example of Observational Study

• The example of Experimental Study

Ms. Rivera, a teacher, organizes an experiment over two weeks during recess. She divides her students into two groups: Group A participates in structured group activities, such as team games and collaborative projects. Group B has free play, allowing them to choose their activities without any specific guidance. Assessment: At the end of the two weeks, Ms. Rivera evaluates the children's social interactions by recording instances of cooperative play, communication, and the formation of new friendships in both groups.

• The example of Observational Study

• The example of Experimental Study