CHAPTER 1: MEASUREMENTS Flashcards
is the discipline concerned with the treatment and analysis of numerical data
derived from biological, biomedical, and health related studies.
Biostatistics
The discipline
encompasses a broad range of activities, including the design of research, collection and
organization of data, summarization of results, and interpretation of findings.
Biostatistics
biostatistics encompasses —
broad range of activities
including the design of research
collection and organization of data, summarization of results
interpretation of findings.
is a servant of the sciences.
biostatistics
is more than just a compilation of computational techniques.
Biostatistics
Biostatistics is not merely
pushing numbers through
formulas or computers
it is a way to detect patterns
and judge responses.
Biostatistics
is both a data detective and judge
statistician
who uncovers patterns and clues
data detective
who decides whether the
evidence can be trusted.
judge
3 Goals of biostatistics
improvement of the intellectual content of the data
organization of data into understandable forms
reliance on tests of experience as a standard of validity
it is How we get our data
Measurement
The assigning of numbers or codes
according to prior-set rules.
Measurement
May entail either positioning
observations along a numerical
continuum or classifying observations
into category
Measurement
The unit in which measurements are
made,
Observation
may correspond to individual or
specimens.
Observation
are often collected with the
aid of a data collection form,
Data
data on individual data
forms usually corresponding to
observations
are units upon which measurements are made
Observations
are the characteristics being measured
Variables
are realized measurements.
Values
rows
Observations
columns
Variables
table cells (observation x variables/ rows x columns)
Values
3 TYPES OF MEASUREMENT SCALES
Categorical measurements
Ordinal measurements
Quantitative measurements
it place observations into unordered
categories.
Categorical measurements
observations into classes or
groups
Categorical measurements
It may also be called nominal variables
Categorical measurements
nominal means
named
It may also be called nominal variables (nominal means named), attribute variables, and qualitative variables.
Categorical measurements
place observations into categories that can be put into rank order.
Ordinal measurements
represent numerical values for which arithmetic operations make sense
Quantitative measurements
Some statistical sources use terms such as ratio/interval
measurements, numeric variable, scale variable, and continuous
variable
Quantitative measurements
4 other terms Quantitative measurements
ratio/interval measurements
numeric variable
scale variable
continuous variable
(the intent to measure things as they are without shaping them to conform a preconceived worldview)
Objectivity
is an important part of
measurement accuracy.
Objectivity
It requires a suspension of judgement; it
requires us to look at all the facts, not just the facts that please us.
Objectivity
2 forms of measurement errors:
imprecision and bias.
expresses itself in a measurement as the inability to get the same result upon repetition.
Imprecision
expresses itself as a tendency to overestimate or underestimate the true value of an object.
Bias
