Biostatistics applies statistical tools to biological and medical data. It is used (1) to establish what is considered normal in areas like physiology and anatomy, (2) to determine whether observed differences are due to chance or other factors in areas like comparing drug effectiveness and public health measures, and (3) to identify disease characteristics and evaluate health programs by comparing data from experiment and control groups.

1. Biostatistics

2. Biostatistics is the term used
when tools of statistics are
applied to the data that is
derived from biological sciences
such as medicine.

3. Scope
Certain essential bits of methods in biostatistics,
must be learnt to understand their application in
Diagnosis,
Prognosis–opinion based on medical experience.
Prescription and
Management of diseases in individuals and
community.

4. Statistics in medicine
• Health statistics- public or
community health.
• Medical statistics -efficacy of drug
• Vital statistics - vital events of births,
marriages and deaths.

5. Application and Uses of
Biostatistics as a Science

6. In physiology and anatomy
• To define what is normal or healthy in a
population.
The mean pulse rate is 72 per minute but up
what limits it may be normal on either side of
mean has to be established with certain
appropriate techniques.

7. To find the difference between means
and proportions of normal at two
places or in different periods.
The mean height of boys in Gujarat is less than
the mean height in Punjab. Whether this
difference is due to chance of a natural variation
or because of some other factors such as better
nutrition playing a part, has to be decided.

8. In Pharmacology
• To find the action of drug—a drug is given to
animals or humans to see whether the
changes produced are due to the drug or by
chance.
• To compare the action of two different drugs
or two successive dosages of the same drug.
• To find the relative potency of a new drug
with respect to a standard drug.

9. In medicine
• To compare the efficacy of a particular drug,
operation or line of treatment—for this,
The percentage cured, relieved or died in the
experiment and control groups, is compared and
difference due to chance or otherwise is found
by applying statistical techniques.
• To find an association between two attributes
such as cancer and smoking

10. To identify signs and symptoms of a disease or
syndrome. Cough in typhoid is found by chance
and fever is found in almost every case. The
proportional incidence of one symptom or
another indicates whether it is a characteristic
feature of the disease or not.
In medicine

11. In community medicine and public
health
• To test usefulness of sera and vaccines in the
field
Percentage of attacks or deaths among
the vaccinated subjects is compared
with that among the unvaccinated
ones to find whether the difference
observed is statistically significant.

12. • In epidemiological studies—the role of
causative factors is statistically tested.
Deficiency of iodine as an important
cause of goiter in a community is
confirmed only after comparing the
incidence of goiter cases before and
after giving iodized salt.
In community medicine and public
health

13. • In public health, the measures adopted are
evaluated.
Lowering of morbidity rate in typhoid
after pasteurization of milk may be
attributed to clean supply of milk, if it
is statistically proved.
In community medicine and public
health

14. • Fall in birth rate may be the result of
Family planning methods adopted
under National Family Welfare
Programme or due to rise in living
standards, increasing awareness and
higher age of marriage.
In community medicine and public
health

15. Recording of vital events
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.

16. Biostatistics as a science of figures will
tell:
a. What are the leading causes of death?
b. What are the important causes of
sickness?
c. Whether a particular disease is rising or
falling in severity and prevalence?
d. Which age group, sex, social class of
people, profession or place is affected the
most?

17. Biostatistics as a science of figures will
tell:
e. The levels or standards of health reached.
f. Age and sex composition of population in a
community.
g. Whether a particular population is rising,
falling, aging or ailing?
h. Which health program should be given
priority and what will be the requirements for
the same?