An Example of a Randomized Controlled Experiment Is When

question 2

Multiple Choice

An example of a randomized controlled experiment is when

• A)households receive a tax rebate in one year but not the other.
• B)one U.S. state increases minimum wages and an adjacent state does not, and employment differences are observed.
• C)random variables are controlled for by holding constant other factors.
• D)some 5^th graders in a specific elementary school are allowed to use computers at school while others are not, and their end-of-year performance is compared holding constant other factors.

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Definitions:

Mesozoic Era

A geologic era that occurred about 252 to 66 million years ago, characterized by the dominance of dinosaurs and the appearance of flowering plants.

Mass Extinctions

Events in Earth's history when significant numbers of species disappear rapidly and irreversibly, often due to drastic environmental changes.

Varves

Thin, alternating light-colored and dark layers of sediment that form in lakes because of seasonal variations of deposition and biologic activity.

Ice Cores

Cylinder-shaped samples from ice sheets or glaciers that scientists study to understand past climates.