Basic concepts of biostatistics and its application in Dentistry.

1. INTRODUCTION TO
BIOSTATISTICS

2. A BLACK BELT
For every 10,000 people that join a Martial Arts Academy, HALF will drop out
with-in the first 6 months.
Of those remaining students, about 1,000 will complete 1 year of training and
then quit. 500 will study for 2 years. But only 100 will see their 3rd year
anniversary.
On the average, ONLY 10 will make 1st Degree Black Belt.
Usually, Only 1 will make it to 2nd Degree Black Belt.
So The statistics says that….
If this person is a BLACK BELT!
This person is 1 in 10,000!

3. STATISTICS
IS “A SCIENCE OF FIGURES”……
Helps us make sense of DATA
Is Multi Disciplinary

8. The science of collecting, monitoring, analyzing,
summarizing, and interpreting data.
DEFINITION

9. Statistics applied to biological (life) problems, including :
• Public health
• Medicine
• Ecological and environmental
BIOSTATISTICS

10. WHATISTHEBASISOFSTATISTICAL
REASONING???
VARIATION

11. “If there were no variation, if every observation
were predictable, a mere repetition of what had
gone before, there would be no need for
statistics.”

12. HISTORY

14. PLAGUE OUTBREAK
• During the outbreak of plague in England,
they started publishing the weekly death
statistics.
• This practice continued and these bills of
mortality, listed births and deaths this caught
the attention of CAPT.JOHN GRAUNT.

15. IN 1662, CAPT.JOHN GRAUNT USED 30 YEARS OF THESE
BILLS TO MAKE PREDICTIONS ABOUT THE NUMBER OF
PEOPLE WHO WOULD DIE FROM VARIOUS DISEASES
AND PROPORTIONS OF MALE AND FEMALE BIRTHS
THAT COULD BE EXPECTED.

17. BIOSTATISTICSCANBEBOTHINTERESTINGAND
CHALLENGING….

18. Why Can it be Interesting?
Combines rigors of mathematics with uncertainties of the real world.
Can make contribution to advancement of science, statistics, medicine,
and public health.
Can study diseases/health problems in which you may have an interest
(cancers, HIV, reproductive health, …)

19. WhyisitaChallenge???
Much of life is composed of a systematic component
and a random component.

20. Example:
Smoking is associated with lung cancer.
Yet not everyone that smokes gets lung cancer, and not everyone that
gets lung cancer, smokes.
Yet we know that there is an association (a systematic component)

21. ⊸Our challenge
Identify the systematic component (separate it from the
random component), estimate it, and perhaps make
inferences with it.

22. BIOSTATISTICS CONSTITUTES BACK BONE OF
RESEARCH METHODS
BIOSTATISTICS AND RESEARCH

23. “Delivering modern, high quality care to patients now relies
increasingly on routine reference to scientific papers and
journals, rather than traditional textbook learning”
FROM TEXTBOOKS TO JOURNALS….
HEALTHCARE PARADIGM SHIFT….

24. BIOSTATISTICS
BASICS

25. 25
PopulationsandParameters
Population
A group of individuals that we
would like to know something
about.
Parameter
A characteristic of the population in
which we have a particular interest.
Often denoted with Greek letters
(μ, σ, ρ)
µ = POPULATION MEAN

26. 26
Samples and Statistics
Sample
A subset of a population
(hopefully representative)
Statistic
A characteristic of the sample
𝒙 = SAMPLE MEAN

27. SUBDIVISIONS OF STATISTICS THEY CAN BE SEPARATED INTO TWO
BROAD CATEGORIES:
1.DESCRIPTIVE STATISTICS 2.INFERENTIAL STATISTICS
Numbers used to summarize and
describe data
Make inferences about the
population using what is observed
in the sample.

28. DESCRIPTIVE STATISTICS

29. INFERENTIAL STATISTICS

30. SUMMARY
• STATISTICS - THE SCIENCE OF NUMBERS
• HISTORY – JOHN GRAUNT AND BILLS OF MORTALITY
• BIOSTATISTICS - INTERESTING AND CHALLENGING
• BIOSTATISTICS BASICS
- Population and Parameters
- Sample and Statistics
• TYPES
- Descriptive
- Inferential