The Sample Standard Deviations for X and Y Are 10

question 119

Multiple Choice

The sample standard deviations for x and y are 10 and 15, respectively. The covariance between x and y is −120. The correlation coefficient between x and y is ________.

• A) −0.8
• B) −0.5
• C) 0.5
• D) 0.8

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Definitions:

Short Run

A period in economics during which at least one input, such as plant size or capital, is fixed and cannot be changed.

Variable Costs

Variable costs are expenses that change in proportion to the activity or volume of business, such as materials and labor costs.

Fixed Inputs

Resources used in production that cannot be easily increased or decreased in a short period.

Marginal Cost

The cost of producing an additional unit of a good or service.