Observational Study or Experiment?

One study of cell phones and the risk of brain cancer looked at a group of 469 people who have brain cancer. the investigators matched each cancer patient with a person of the same age, gender, and race who did not have brain cancer, then asked about the use of cell phones. Their results suggested that the use of handheld cell phones is not associated with risk of brain cancer.

Is this an observational study or an experiment?

• Observational Study

• Experiment

Tags

CCSS.HSS.IC.B.3

A study wanted to detemine if chocolate consumption during pregnancy had an effect on infant temperament at age 6 months. Researchers began by asking 305 healthy pregnant women to report their chocolate consumption. Six months after birth, the researchers asked mothers to rate their infants temperament. The babies born to wormen who had been eating chocolate daily during pregnancy were found to be more active and "positively reactive".

Is this an observational study or an experiment?

• Observational Study

• Experiment

Tags

CCSS.HSS.IC.B.3

A study of child care enrolled 1364 infants and followed them through their sixth year in school. Later, the researchers published an article in which they stated that "the more time children spent in child care from birth to age 4.5, the more adults tended to rate them as more assertive, disobedient, and aggressive.

Is this an observational study or an experiment?

• Observational Study

• Experiment

Tags

CCSS.HSS.IC.B.3

A high school is offering two options for an SAT prep course: an online course and an in-person course. The school is interested in seeing which instructional method is more effective. Fifty students are asked to participate. Twenty five students are randomly assigned to the online course and the other 25 are assigned to the in-person course. The students' SAT scores are compared.

Is this an observational study or an experiment?

• Observational Study

• Experiment

Tags

CCSS.HSS.IC.B.3

An educator wants to compare the effectiveness of computer software for teaching biology with that of a textbook presentation. She gives a biology pretest to each of the group of high school juniors, then randomly divides them into two groups. One group uses the computer and the other studies the text. At the end of the year, she tests all the students again and compares the increase in biology test scores in the two groups.

Is this an observational study or an experiment?

• Observational Study

• Experiment

Tags

CCSS.HSS.IC.B.3