engineering estimations &approximations Flashcards
measurement
Measurement is the comparison with a standard.
Measurements are made using Analog and Digital
methods
analog measurement
Humans perceive their surroundings as a continuous
transmission of information. This non‐stop stream of information is defined as
Analog information
digital measurement
Digital information is an estimation of real world
analog information.
The process of obtaining digital information is known
as Analog‐to‐Digital Conversion (ADC)
analog v digital
analog is more accurate, digital is easier to manipulate
taking measurements
Engineering requires measurements to be made
concerning the physical qualities that influence a
design solution.
One cannot assume that a measurement is exact.
The use of Significant Figures provides a way of
showing how “good” a measured value is.
significant figure/digit
Constants & Conversion Factors
Considered an exact value.
Exact values have an infinite () number of
significant digits.
Will not influence the Significant Digit count of a
final answer.
accuracy
Accuracy is the closeness of an observation or
measurement to its true value.
precision
the quality or state of being precise: exactness
systematic error
a type of error that deviates by a fixed amount from the true value of measurement, all measuremnts are prone to systematic errors.because systematic error is fixed over the range of the measurement it is often referred to as a bias
sources of systematic error
uncalibrated measurement device (easy to correct), environmental changes which interfere with the measurement process (difficult to identify and correct), imperfect of incorrect method of taking the measurement
random error
a type of error that adds variability to the measurement but does not affect average performance for the group, random error is the result of uncontrolled factors affecting the measurement across the sample, referred to as measurement noise
