A Study Has Indicated That the Sample Size Necessary to Estimate

question 29

Multiple Choice

A study has indicated that the sample size necessary to estimate the average electricity use by residential customers of a large western utility company is 900 customers. Assuming that the margin of error associated with the estimate will be ±30 watts and the confidence level is stated to be 90 percent, what was the value for the population standard deviation?

• A) 265 watts
• B) Approximately 547.1 watts
• C) About 490 watts
• D) Can't be determined without knowing the size of the population.

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Definitions:

First-Order Model

A mathematical or statistical model that represents linear relationships between variables using first-degree equations.

Unit Increase

It refers to the increment by a single unit in the independent variable and observing the effect on the dependent variable.

Holding Constant

A method in analysis where certain variables are kept unchanged to isolate the effect of varying other variables.

Simple Linear Regression

A mathematical approach that establishes a connection between a dependent variable and a single independent variable through the application of a linear equation to the collected data.