Observational Studies and Experiment Review

One group of subjects was given an herbal supplement and another group was given a placebo. After one year, the number of illnesses each group had was compared.

• Observational Study

• Experiment

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

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

Tags

CCSS.HSS.IC.B.3

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

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

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

• experiment

• observational study

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

Double blind is an experimental procedure in which both the research participants and the research staff are ignorant about whether the research participants have received the treatment or a placebo.

• True
• False

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

To be a true experiment, it must use

• random assignment

• case studies

• predictions

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

an inactive substance or fake treatment used to control for confounding variable

• Causation

• Evolution

• Placebo

• Independent Variable

Tags

CCSS.HSS.IC.B.5

An advertising agency is testing the effectiveness of a new commercial. They are trying out the commercial in three different time lengths (15, 30, and 60 seconds) and two formats (animated vs. live action). Each test audience will rate the product after seeing the commercial shown in one way. Which description is correct?

• An experiment with 2 factors (length and format), one having 3 levels (15, 30, 60) and the other having 2 levels (animated and live) for 6 treatments.

• An experiment with 2 factors (length and format) at 5 levels (15, 30, 60, animated and live) for 5 treatments.

• An experiment with 1 factor (length) blocked by format with 3 levels (15, 30, 60).

• A sample survey with two questions and one response.

• A sample stratified by length and format.

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

Which is one of the main differences between experiments and observational studies?

• There is a response variable in an experiment, but not in an observational study.

• There is at least one explanatory variable in an experiment, but not in an observational study.

• An experiment requires blocking, while an observational study does not.

• An experiment can be used to establish a causal relationship, but an observational study cannot.

• Observational studies require larger samples than experiments.

Tags

CCSS.HSS.IC.B.3

A local news program decides to conduct a poll to see how their viewers feel about their programming format. At the end of each program during one week they ask viewers to call in and express their opinions. The station gives one number to dial if you like the new format, and another to dial if you do not like it. Which of the following is a correct characterization of this sampling approach?

• This sampling approach will be biased because people might dial the number incorrectly, and therefore not everyone will be correctly represented.

• This sampling approach will be biased because the people who call in will be those who have stronger feelings about the new format, and therefore the sample will not be representative of the population.

• This sampling approach will be unbiased because people can call in with either opinion, and therefore the sample will be representative of the population.

• This sampling approach will be unbiased because the station doesn't know who will call in, making it a random sample.

• It is impossible to tell whether this sampling approach will be biased or not because the station cannot predict who will call in.

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.A.1