Using R and RStudio for Data Management, Statistical Analysis, and Graphics, 2nd Edition

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“K23166” — 2015/1/28 — 9:35 — page 38 — #64

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38 CHAPTER 3. STATISTICAL AND MATHEMATICAL FUNCTIONS

Note: The second parameter of the round() function determines how many decimal places

to round. The value of movetozero is the same as justint if x > 0 or nextint if x < 0.

3.2.5 Comparisons of floating-point variables

Because certain floating-point values of variables do not have exact decimal equivalents,

there may be some error in how they are represented on a computer. For example, if the

true value of a particular variable is 1/7, the approximate decimal is 0.1428571428571428.

For some operations (for example, tests of equality), this approximation ...