The Oxidation of Iron to Rust Is a Problem Structural

question 99

Multiple Choice

The oxidation of iron to rust is a problem structural engineers need to be concerned about,but the oxidation of aluminum to aluminum oxide is not so much of a problem.Why?

• A)Since aluminum is so light and inexpensive,it is easily replaced when corroded.
• B)Aluminum oxide is insoluble in water and thus forms a protective coating that prevents continued oxidation of the aluminum.
• C)Aluminum oxide is even stronger than aluminum.
• D)The oxidation of aluminum is a very slow reaction,taking hundreds of years before any structural changes are noticed.

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Definitions:

Test Statistic

A value, derived from sample data, used in a hypothesis test to determine whether to reject the null hypothesis.

Durbin-Watson Statistic

A test statistic used to detect the presence of autocorrelation in the residuals from a linear regression analysis.

Multiple Regression Model

A predictive method in statistics that uses a range of explanatory variables to estimate the result of a dependent variable.

Independent Variables

Variables in an experiment or statistical model that are manipulated or categorized to determine their effect on dependent variables without being affected by any other variable in the model.