How Would You Correctly Refer to the Metamorphic Grade of a Rock

question 4

Multiple Choice

How would you correctly refer to the metamorphic grade of a rock that contains bundles of fibrous sillimanite along with pyroxene and sanidine as its highest temperature minerals such as a coarse grained granulite facies gneiss?

• A) high grade > 600° C
• B) intermediate grade
• C) "S grade"
• D) low grade < 200° C

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Definitions:

Confidence Estimate

A range of values used to estimate a parameter, calculated in such a way that it is likely, to a specified level of confidence, to contain the true value of the parameter.

Confidence Interval

A set of values, calculated from sample statistics, predicted to hold the value of an unobserved population parameter.

Standard Deviation

A measure of the amount of variation or dispersion of a set of values, indicating how much the values differ from the mean.

T-Distribution

A probability distribution used in statistics that arises when estimating the mean of a normally distributed population in situations where the sample size is small and population variance is unknown.