Which of the Following Statements Best Describes What Has Happened

question 18

Multiple Choice

Which of the following statements best describes what has happened to air quality since the United States outlawed the use of chlorofluorocarbons, halons, and carbon tetrachloride?

• A) Air quality immediately improved.
• B) Air quality is slowly improving.
• C) Little change occurred because these chemicals remain in the atmosphere.
• D) Nothing has happened because other countries worldwide continue to extensively use these products.

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Definitions:

Median

A statistical measure representing the middle value in a sorted, ascending or descending, list of numbers.

Mode

The value that appears most frequently in a given set of data, or a specific way or manner in which something occurs or is experienced.

Degrees of Freedom

The number of independent values or quantities which can be assigned to a statistical distribution without violating any constraints.

Mean

A measure of central tendency in statistics, representing the average of a set of numbers, calculated by dividing the sum of the values by the number of values.