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Numbers and Percentages

Stephen J. Lurie

and Margaret A. Winker

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Subscriber: null; date: 22 September 2017


The decimal form should be used when a fraction is given with an abbreviated unit of measure (eg, 0.5 g, 2.7 mm) to reflect the precision of the measurement (eg, 38.0 kg should not be rounded to 38 kg if the scale was accurate to tenths of a kilogram). (See also 18.4.2, Units of Measure, Use of Numerals With Units, Decimal Format.)

The patient was receiving gentamicin sulfate, 3.5 mg/kg, every 8 hours. Her serum gentamicin level reached a peak of 5.8 μg/mL and a trough of 0.7 μg/mL after the third dose.

Place a zero before the decimal point in numbers less than 1, except when expressing the 3 values related to probability: P, α, and β. These values cannot equal 1, except when rounding (see 20.9, Study Design and Statistics, Glossary of Statistical Terms). Because they appear frequently, eliminating the zero can save substantial space in tables and text. (Although other statistical values also may never equal 1, their use is less frequent, and to simplify usage, the zero before the decimal point is included.)

P = .16

1 − β = .80

Our predetermined α level was .05.

But: κ = 0.87

Note, however, that α and β may sometimes be used to indicate other statistics, and in some of these cases their values may be 1 or greater.

Cronbach α = 0.78

standardized β coefficient = 2.34

By convention, a zero is not used in front of the decimal point of the measure of the bore of a firearm.

.22-caliber rifle

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