Units, Measurements, Accuracy, and Precision

• 1 in = 2.54 cm (exactly)
• 1 mile = 1.609 km
• 1 mile = 5280 ft (exactly)
• 1 lb = 0.454 kg
• 1 lb = 16 oz
• 1 oz = 28.35 g
• 1 grain = 64.80 mg
• 1 L = 1 dm^3
• 1 gal = 3.79 L
• 1 mL = 1 cm^3
• 1 cc = 1 cm^3

Example Problems

• An operating table from Acme Surgical Supply can support a total of 50 kg, which is equivalent to a weight of 110 lbs., the largest patient the table can support.
• An infant that weighs 144 oz. at birth weighs 9 lbs.

Accuracy and Precision of Measurement

• Science is based on observation and experiment.
• Accuracy is how close a measurement is to the correct value for that measurement.
• Precision refers to how close the agreement is between repeated measurements under the same conditions.
• One way to analyze measurements is to determine the difference between the lowest and highest measured values.

Errors in Measurement

• Systematic errors always produce an error of the same sign, making observations too low or too high and may be due to personal, instrumental, or external factors.
• Random errors often result from limitations in the equipment or techniques used.

Clinical Measurements

• Some routine measurements include vital signs, body mass index, symphysis fundal height, mid-upper arm circumference, and range of motion.

Vital Signs

• Vital signs measure the body's most basic functions.
• Are routinely monitored by medical and healthcare professionals.
• Vital signs include body temperature, pulse rate, respiration rate, blood pressure, weight, and height.