Intoduction to biostatistics

INTRODUCTION TO
BIOSTATISTICS
PRESENTED BY :-
DR SAKSHI KAUR CHHABRA
2ND YEAR POST GRADUATE
DEPARTMENT OF PUBLIC HEALTH DENTISTRY

STATISTICS
 STATIC or DATUM means a measured or counted fact or
piece of information stated as a figure such as height of one
person, birth of a baby, etc.
 They are collected from records, experiments and surveys,
in all walks of life such as economics, politics, education,
industry, business, administration etc. Medicine too,
including preventive medicine and public health, in such
field.

STATISTICS
 A simple but concise definition by Croxton and
Cowden :-
‘Statistics is defined as the
1. Collection
2. Organization
3. Presentation
4. Analysis
5. Interpretation of numerical data.’

biostatistics
 It is the branch of statistics concerned with
mathematical facts and data related to biological
events.
 It is the science that helps in managing medical
uncertainties.

biostatistics
 Biostatistics covers applications and contributions not only from health, medicines
and, nutrition but also from fields such as genetics, biology, epidemiology, and many
others.
 It is mainly consists of various steps like generation of hypothesis, collection of data,
and application of statistical analysis.

APPLICATIONOF BIOSTATISTICS
[1] AS A SCIENCE
[2] AS A FIGURES

[1] AS A SCIENCE
A. IN COMMUNITY MEDICINE AND PUBLIC HEALTH
B. IN PHYSIOLOGY AND ANATOMY
C. IN PHARMACOLOGY
D. IN MEDICINE
E. IN CLINICAL MEDICINE
F. IN PREVENTIVE MEDICINE

[A] IN PUBLICHEALTH
1) To evaluate the efficacy of sera and vaccines in the field.
2) In epidemiological studies - the role of causative factors is statistically tested.
3) To test whether the difference between two populations is real or a chance
occurrence.
4) To study the correlation between attributes in the same population.

5) To measure the morbidity and mortality.
6) To evaluate achievements of public health programs.
7) To fix priorities in public health programs.
8) To help promote health legislation and create administrative standards for oral health.
9) It helps in compilation of data, drawing conclusions and making recommendations.
10) For students of medicine/dentistry

[B] IN PHYSIOLOGY ANDANATOMY
1) To define what is normal or healthy in a population.
2) To find the limits of normality in variables such as weight and pulse rate etc. in a
population.
3) To find the difference between means and proportions of normal at two places or
in different periods.

[C] IN PHARMACOLOGY
1) To find out the action of drug.
2) To compare the action of two different drugs or two successive dosages of the same
drug.
3) To find the relative potency of a new drug with respect to a standard drug.

[D] IN MEDICINE
1) To compare the efficacy of a particular drug, operation or line of treatment.
2) To find an association between two attributes such as cancer and smoking or
filariasis and social class.
3) To identify signs and symptoms of a disease or syndrome.
4) In epidemiological studies – the role of causative factors is statistically tested.

[E] IN CLINICAL MEDICINE
1) Documentation of medical history of diseases.
2) Planning and conduct of clinical studies.
3) Evaluating the merits of different procedures.
4) In providing methods for definition of ‘normal’ and ‘abnormal’.

[F] IN PREVENTIVE MEDICINE
1) To provide the magnitude of any health problem in the community.
2) To find out the basic factors underlying the ill-health.
3) To evaluate the health programs which was introduced in the
community(success/failure).
4) To introduce and promote health legislation.

[2] AS A FIGURES
 Health and vital statistics are essential tools in demography, public health, medical
practice and community services.
 Recording of vital events in birth and death registers and diseases in hospitals is like
book keeping of the community, describing the incidence or prevalence of diseases,
defects or deaths in a defined population.

Such events properly recorded form the eyes and ears of a public health or medical
administrator.
1) What are the leading causes of death?
2) What are the important cause of sickness?
3) Whether a particular disease is rising or falling in severity and prevalence? etc.

USES OF STATISTICS IN DENTAL SCIENCE
1. To find the statistical difference between means of two groups. Ex: Mean plaque
scores of two groups.
2. To assess the state of oral health in the community and to determine the availability
and utilization of dental care facilities.
3. To indicate the basic factors underlying the state of oral health by diagnosing the
community and find solutions to such problems.

4. To determine success or failure of specific oral health care programs or to
evaluate the program action.
5. To promote oral health legislation and in creating administrative standards for
oral health care delivery.

data
 A collective recording of observations either numerical or otherwise.
 A collection of facts from which conclusions may be drawn.

COLLECTIONOF DATA
 Demographic data comprise details of population size, geographic distribution, ethnic
groups, socio-economic factors etc.
 Such data are obtained from :-
1. Census
2. Experiments
3. Surveys
4. Hospital records
5. Other public health reports
6. Oral health care programmes

Classification of data
 Depending on the nature of the variable, data is classified into 2 broad categories :-
A. QUALITATIVE DATA
B. QUANTITATIVE DATA

Classification of data[A] QUALITATIVE DATA
When the data is collected on the basis of qualities like sex, malocclusions, cavity etc.
[B] QUANTITATIVE DATA
When the data is collected through measurement using calipers like arch length, arch width,
fluoride concentration in water supply etc.

QUALITATIVE DATA
 DISCRETE DATA :- When the variable under observation takes only fixed values
like whole numbers, the data is discrete. DMFT, no. of children ( counted items ).
 CONTINOUS DATA :- If the variable can take any value in a given range, decimal or
fractional, it is called as continuous data like arch length, mesiodistal width of the
erupted teeth. ( measured characteristics )

QUantiTATIVE DATA
 NOMINAL DATA :- Consists of named categories, with no implied order among the
categories.
 ORDINAL DATA :- Consists of ordered categories, where differences between
categories cannot be considered to be equal. Ex- Likert’s scale.

DATA CAN BE COLLECTEDTHROUGH
[A] PRIMARY SOURCE :- Here the data is obtained by the investigator himself. This is
first hand information.
[B] SECONDARY SOURCE :- The data is already recorded is utilized to serve the
purpose of the objective of the study. EXAMPLE –
records of the OPD of dental clinics.

COLLECTIONOF PRIMARY DATA
1) DIRECT PERSONAL INTERVIEWS
2) ORAL HEALTH EXAMINATION
3) QUESTIONNAIRE BASED

[1] DIRECT PERSONAL INTERVIEWS

[2] ORAL HEALTHEXAMINATION
It is conducted by dentist and dental auxiliary personnel

[3] QUESTIONNAIRE METHOD
 In this method, a list of questions
pertaining to the survey, known
as questionnaire, is prepared and
the various informants are
requested to supple the
information either personally or
via post.
 This method is easy to adopt
when a wide geographic area is
covered.

CONCLUSION
 Bio-statistical techniques can assure that the results found in such a study are not
merely because of chance.
 In every case of our life, Statistics plays a major role for better gaining and accurate
results.
 A well-designed and properly conducted study is a basic prerequisite to arrive at
valid conclusions.

Intoduction to biostatistics

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Intoduction to biostatistics