Most electronic equipment use _______ _______ for measurement of variables.
What do the sensing equipment use to measure the physical phenomena?
How do the transducers work?
The output of transducers is always an electric signal which is representative of the phenomena measured
How is the data from the transducers read?
the signal from the transducer is amplified or modified; then display equipment transforms the signal by the signal-conditioning equipment which allows visualization of the waveform of a signal by displaying time, phase, voltage, or frequency of a physiological input signal
What is artifact?
extraneous components of a signal which can affect readings
What are some sources of artifact?
noise, the subject, & problems in calibration of the instrument
What are biochemical measurements?
they involve the use of chemical laboratory procedures for the identification or quantification of biochemical physiological variables, such as serum hormone or electrolyte levels
What are some techniques used to obtain biochemical measurements?
The first step of measuring biochemical variables involves...
collection of the specimen. Ensure proper procedure is followed and the proper amount is obtained and proper container is used
The second step of measuring biochemical variables involves...
preservation and storage of the specimen. The storage temperature and type of container can affect reliability.
The third step of measuring biochemical variables involves...
following all established guideline regarding type of equipment, laboratory guides, and manuals.
The fourth step of measuring biochemical variables involves...
ensuring equipment is in good working order and is tested at periodic intervals. Use proper reagents or substances when producing chemical reactions and ensure they are not outdated
The fifth step of measuring biochemical variables involves...
reading and recording the results. Miscalculations can affect reliability and validity.
What are microbiologic/microscopic measurements?
consists of identifying or quantification of microorganisms; measurement consists of identification of microorganisms within physiological specimens (bacteria, molds, protozoa) and the identification or quantification of structure and components of bodily tissues (bacterial counts, cell histology)
The process of collecting, preserving, analyzing, and recording the results of microbiologic/microscopic specimens is very similar to those of _______ _______.
What are some disadvantages associated with physiological measures?
1. they are often costly and time-consuming to analyze 2. often the measurement protocol involves complex, multi-step procedures 3. at each point in the protocol, there is the possibility of errors 4. often the techniques of using the measure are complex and difficult to learn
What are some sources of intra-individual variability?
What would be better to use, Cohen's kappa/percent of agreement or the correlation coefficient?
Cohen's kappa/percent of agreement
What is accuracy?
measures the correctness of the physiological measures.
How is the level of accuracy determined?
by the selectivity, sensitivity, and specificity of measure
What is selectivity?
refers to the ability of an instrument to identify correctly under study and differentiate it from all other signals
What is sensitivity?
in bioinstrumentation, it refers to the smallest amount of change in a parameter that can be detected or measured precisely
How could content validity be evaluated?
by contacting the experts in lab procedures or bioinstrumentation. They can review the approach or methods used and determine if they are appropriate for the physiologic variable being measured
How could construct validity be evaluated?
it can be tested by using contrasted groups and/or experimental methods approaches. Contrasted groups are used when one group of subjects who are known to be high on a trait are contrasted to another group who are known to be low on the trait being tested