Observational Study or Experiment and Identify Treatments

To test the effects of breakfast on grades I ask my students if they ate breakfast and then compare the breakfast eaters grades to the non-breakfast eaters. This is an example of:

• 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

Researchers were interested to know whether internal vehicle temperatures vary by outside temperatures. To evaluate this, temperature rise was measured continuously over a 60-minute period in a dark SUV on 16 different clear, sunny days with outside temperatures ranging from 72^oF to 96^oF. The researchers' method of analysis is best described as:

• a census.

• a survey.

• an observational study.

• an experiment.

Individuals are observed and variables are measured without controlling the individuals or the environment

• population

• observational study

• experiment

• secondary data

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

• Experiment

• Observational Study

To test the effects of breakfast on grades I ask my students if they ate breakfast and then compare the breakfast eaters grades to the non-breakfast eaters.
This is an example of:

• Observational study

• Experiment

• Neither

• Both observational study and experiment

A University of Helsinki (Finland) study wanted to determine 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, including smiling, laughter, and fear. The babies born to women who had eaten chocolate daily during pregnancy were found to be more active and “positively reactive”—a measure that the investigators said encompasses traits like smiling and laughter. Is this an observational study or an experiment? Explain your answer.

• This is an experiment. There were no treatments imposed on the healthy pregnant women.

• This is an experiment. There were treatments imposed on the healthy pregnant women.

• This is an observational study. There were no treatments imposed on the healthy pregnant women.

• This is an observational study. There were treatments imposed on the healthy pregnant women.

A study of child care followed 1364 infants 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 four-and-a-half, the more adults tended to rate them, both at age four-and-a-half and at kindergarten, as less likely to get along with others, as more assertive, as disobedient, and as aggressive.” Is this an observational study or an experiment? Explain your answer.

• This is an experiment. There were no treatments imposed on the infants.

• This is an experiment. There were treatments imposed on the infants.

• This is an observational study. There were no treatments imposed on the infants.

• This is an observational study. There were treatments imposed on the infants.