BIOSTATS Flashcards
Study of distribution and determinants of health-related events in specified population for
prevention and control
EPIDEMIOLOGY
Percentage of population that has disease during given
time period
Prevalence
Percentage of population that contracts a disease in a
given time period or number of new people who gets
the disease
Incidence
- More exploratory
- Profiles characteristics
of groups - Focuses on “what”
- Assumes no
hypothesis - Does not require
comparisons between
groups over time
DESCRIPTIVE
Explains
- More explanatory
- Analyzes why groups
has characteristics
- WHY
- Assumes a hypothesis
- Require comparison
bet groups over time
ANALYTICAL
Diseases (or any health-related events) don’t occur at
random
- Diseases (or other health events) have causal and
preventive factors which can be identified through
systematic investigation of population
- Epidemiology focuses on populations rather than
individual persons, tissues, or organ
Epidemiological Principles
science, which deals with collection, presentation,
analysis, and interpretation of numerical data
Statistics
study of probability distributions, sampling
distributions, estimation, hypothesis testing, variance
analysis, regression, and correlation analysis in
healthcare settings
BIOSTATISTICS
Collection, organization, summarization, and
presentation of data
Descriptive Stats
- Generalizing from samples to population, performing
estimations and hypothesis tests, determining
relationships among variables and making predictions - Uses probability
Inferential Stats
Collection of all subjects of interest
Population
Units on which characteristics are measured
Subjects
Subset of population of interest
Sample
Characteristics which are being measured
and/or recorded.
Variables
Representations or each subject characteristic
Data Elements
A Collection of Data
Data Set
substance with no medical benefits or harm
Placebo
decision-making process for evaluating
claims about a population, based on information obtained
from samples.
Hypothesis Testing
categorizes data into distinct, non-overlapping groups
without any inherent order or ranking
- gender, hair color, type of pet, marital status, blood
type
- nationality, blood group, type of vaccines
NOMINAL
organizes data into categories that are rank able, yet it
does not establish exact differences between these
ranks
- education level, movie ratings, military ranks,
satisfaction levels
- pain level, Likert scale, hotel star ratings
ORDINAL
ranks data, and precise differences between units of
measure do exist; however, there is no meaningful zero
- temperature, IQ and SAT scores, calendar years
- time of day on 12 hours clock, pH levels, score on
depression scale
- heart rate, blood pressure, respiratory rate
INTERVAL
possesses all the characteristics of interval
measurement, and there exists a true zero. In addition,
true ratios exist when the same variable is measured
on two different members of the population
- height, weight, age, income
- blood glucose level, dosage of medication, oxygen
saturation levels, time on ventilator
RATIO
branch of mathematics working with data collection,
organization, analysis, interpretation and presentation
(Muhrey, 2008)
Statistics
science of conducting studies to collect, organize,
summarize, analyze, and draw conclusions from data
(Bluman, 2012)
Statistics
application of statistics to problems in the biological
sciences, health, and medicine
Biostatistics
characteristic or attribute that can assume a different
value; e.g. Gender, Intelligence Quotient
Variable
values that a variable can assume
Data
complete enumeration of population, best
source of data on population size and distribution
according to age
Census
evaluating health status of a
population
Prevalence Survey
Identify risk factors
Risk Factor Investigation
Act of selecting participants from a particular
population
Sampling
If total population or sampling frame is less than 50
- If your sample size is less than 30
Non-probability
also known as expert judgement
Purposive sampling
everyone has a chance to be picked
o Toss coin
o Computer assisted
o Random numbers
o Fish bowl
Simple random sampling
K = N/n – same with simple
random but there is a system applied
Systematic Sampling
inclusion of subgroups
within the population like drug users —- teen and
adults ——male and female
o You group your population to certain traits or
attitude
o Strata
Stratified random sampling
is a procedure for selecting sample
elements from a fully defined population
Sampling method
Smaller but hopefully reperesentative collection of
units
Sample
List from which the potential respondents are drawn
Sampling Frame
rom theoretical population to the study population to
sampling frame to the sample
Sampling Breakdown
Techniques used by researchers to
summarize and report data about populations and samples.
- methods concerned w/ collecting,
describing, and analyzing a set of
data without drawing conclusions
(or inferences) About a large group
Descriptive Statistics:
methods concerned with the
analysis of a subset of data leading
to predictions or inferences about
the entire set of Data
INFERENTIAL
STATISTICS
Using tables to organize data.
Tabular
Using various graphs to visualize data.
Graphical
: Identifying the positioning of data.
Location
Displaying the spread of data.
Variation
Showing how data values are distributed
Distribution
summarizes a data set by giving a “typical value”
within the range of the data values that describes its location relative to
entire data set.
Measure of Location
is the smallest value in the data set, denoted as MIN.
Minimum
is the largest value in the data set, denoted as MAX.
Maximum
A single value that is used to identify the “center” of the data
– it is thought of as a typical value of the distribution
– precise yet simple
– most representative value of the data
MEASURES OF CENTRAL TENDENCY
Most common measure of the center
* Also known as arithmetic average
MEAN
- Divides the observations into two equal parts
MEDIAN
in Median If n is odd, the median is the _____________________
middle number.
in Median If n is even, the median is the average of the ________________
2 middle numbers
may not be an actual observation in the data set
* can be applied in at least ordinal level
* a positional measure; not affected by extreme values
Median
occurs most frequently nominal average
* computation of the mode for ungrouped or raw data
MODE
sampling stability is desired
* other measures are to be computed
MEan
the exact midpoint of the distribution is desired
* there are extreme observations
Median
when the “typical” value is desired
* when the dataset is measured on a nominal scale
Mode
Numerical measures that give the relative position of a data value
relative to the entire data set.
Percentiles
- Divide an array into ten equal parts, each part having ten percent of the
distribution of the data values, denoted by Dj
DECILE
- Divide an array into four equal parts, each part having 25% of the
distribution of the data values, denoted by Qj.
QUARTILES
________________________ is a single value that is used to describe the
spread of the distribution
* A measure of central tendency alone does not uniquely describe a
distribution
measure of variation
The difference between the maximum and minimum value in a data set,
i.e. R = MAX – MIN
RANGE
The larger the value of the range, the more dispersed the observations
are.
* It is quick and easy to understand.
* A rough measure of dispersion.
Range
most important measure of variation
* square root of Variance
* has the same units as the original data
STANDARD DEVIATION (SD)
- Describes the extent of peakedness or
flatness of the distribution of the data.
MEASURES OF KURTOSIS
Refers to way observations of a given variable behave in terms of
absolute, relative and cumulative frequencies
FREQUENCY DISTRIBUTION
