All of the Following Features of a Relational Query or of the Relational

question 51

Multiple Choice

All of the following features of a relational query or of the relational database that it accesses are considered by the relational query optimizer, except ____.

• A) whether a search argument in the query is a unique attribute in the database
• B) whether a search argument in the query involves an indexed attribute
• C) the number of rows of output the query produces
• D) the number of rows of the database tables involved
• E) whether a join attribute in the query involves an indexed attribute

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Definitions:

Interval Estimate

An estimation that specifies a range within which a parameter lies, providing an interval believed to encompass the true value of that parameter.

Sample Mean

The average of all the values in a sample set of data.

Confidence Interval

A span of values, taken from sample statistics, seen as likely to encase the value of an unidentified population parameter.

Confidence Level

The probability, expressed as a percentage, that a parameter lies within a specified range of values (confidence interval).