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BIOSTATICS PPT

1. BIOSTATICS PCMS Peshawar

2. STATISTICS STATISTICS- is a science of compiling, classifying, and tabulating numerical data and expressing the results in a mathematical and graphical form. PCMS Peshawar

3. BIOSTATISTICS BIOSTATISTICS- is that branch of statistics concerned with the mathematical facts and data related to biological events. PCMS Peshawar

4. • Constant Constant – Quantities that do not vary e.g. in biostatistics, mean, standard deviation are considered constant for a population PCMS Peshawar

5. • Variable Variable – Characteristics which takes different values for different person, place or thing such as height, weight, blood pressure PCMS Peshawar

6. • Parameter Parameter – It is a constant that describes a population e.g. in a college there are 40% girls. This describes the population, hence it is a parameter. PCMS Peshawar

7. • Statistic Statistic – Statistic is a constant that describes the sample e.g. out of 200 students of the same college 45% girls. This 45% will be statistic as it describes the sample PCMS Peshawar

8. WHY STATISTICS?? • Variability in measurement can be handled using statistics. Eg : investigator makes observations according to his judgment of the situation. (Depending upon his skills, knowledge, and experience.) PCMS Peshawar

9. • Epidemiology and Biostatistics are sister sciences or disciplines. PCMS Peshawar

10. By definition, epidemiology is the study (scientific, systematic, and data-driven) of the distribution (frequency, pattern) and determinants (causes, risk factors) of health-related states and events (not just diseases) in specified populations (neighborhood, school, city, state, country, global). Epidemiology PCMS Peshawar

11. OR Epidemiology is the study and analysis of the distribution, patterns and determinants of health and disease conditions in defined population. It is a cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. PCMS Peshawar

12. • Epidemiology collects facts relating to group of population in places, times and situation. PCMS Peshawar

13. • Biostatistics converts all the facts into figures and at the end translates them into facts, interpreting the significance of their results. • Epidemiology and biostatistics both deal with the facts-figures-facts PCMS Peshawar

14. QUANITATIVE METHADOLOGY PCMS Peshawar

15. USES OF BIOSTATISTICS To test whether the difference between two populations is real or by chance occurrence. To study the correlation between attributes in the same population. To evaluate the efficacy of vaccines. To measure mortality شرح اموات and morbidity بیماری . To evaluate the achievements of public health programs To fix priorities in public health programs To help promote health legislation and create administrative standards for oral health. PCMS Peshawar

16. COLLECTION OF DATA • The collective recording of observations either numerical or otherwise is called data. • Demographic data comprises details of population size, distribution, geographic distribution , ethnic group نسلی گروہ , socio-economic factors سماجی و اقتصادی عوامل and their trends over time. • It is obtained from census and other public service reports. PCMS Peshawar

17. • Depending upon the nature of the variable, data is classified into: Qualitative Data- attributes or qualities. a) Discrete b) Continuous 2. Quantitative data- through measurements using calipers. PCMS Peshawar

18. SOURCES OF STATISTICAL DATA Data can be collected EXPERIMENTS SURVEYS RECORDS Performed to collect data for investigations and research by one or more workers. Carried out for Epidemiological studies in the field by trained teams to find incidence or prevalence پھیلاؤ of health or disease in a community. Records are maintained as a routine in registers and books over a long period of time provide readymade data. PCMS Peshawar

19. PRIMARY SECONDARY Data obtained by the investigator himself. Data has already recorded. Eg : hospital records Primary data can be obtained using any one of the following methods: Direct personal interviews Oral health examination Questionnaire method •Face-to-face contact with the person. •Subjective phenomena. •Accurate and any ambiguity ابہام can be clarified. •Cannot be used in extensive وسیع studies. • When information is needed on health status. • Includes treatment • List of Questions pertaining متعلقہ to the survey “questionnaire” is prepared. • Various informants are requested to supply the information. PCMS Peshawar

20. • Population :- group of all individuals who are the focus of the investigation is known as population. • Census enumeration :- If the information is obtained from each and every individual in the population. • Sample means the group of individuals who actually available for investigation. • Sampling units : the individual entities that form the focus of the study. PCMS Peshawar Sampling and sample design

21. •Representing the population as a whole. • Easy to carry out. •Does not need the preparation of sampling frame. Random selection •Sample of units is selected in such a way that all the characteristics of the population is reflected in the sample. •Random indicates the chance of the population unit being selected in the sample. PCMS Peshawar Sample selection /Purposive selection

22. PCMS Peshawar Sampling Design BASED UPON TYPE AND NATURE OF THE POPULATION AND THE OBJECTIVES OF THE INVESTIGATION.

23. 1. Simple random sampling 2. Systematic random sampling 3 . Stratified random sampling 4 . Cluster sampling 5 . Multiphase sampling PCMS Peshawar

24. • Each and every unit in the population has an equal chance of being included in the sample. • Selection of unit is by chance only. • Population units are numbered on separate slip. • Shuffled and blindfold selection. •Table of random numbers • Selection is done either in a horizontal or vertical direction PCMS Peshawar Simple random sampling

25. • Select one unit at random and then selecting additional units at evenly spaced interval till the sample of required size has been drawn. PCMS Peshawar Systematic random sampling

26. • Population to be sampled is subdivided into groups (age/sex/genetic) known as Strata. ( i.e each group is homogenous in characteristics.) • Then a simple random selection is done from each stratum. • More representative, provide greater accuracy and concentrate on wider geographical area. PCMS Peshawar Stratified random selection

27. • The population forms natural groups or clusters such as village, wards blocks or children of a school. • Sample of the clusters is selected and then all the units in each of the selected cluster is surveyed. • Simpler, less time and cost. • High standard of errors. PCMS Peshawar Cluster sampling

28. • First phase: All the children in school are surveyed. • Second phase: Only the ones with oral health problems. • Third phase: section that needs treatment are selected. • Sub-samples further becomes smaller and smaller. • Adapted when the interest is in any specific disease. PCMS Peshawar Multiphase sampling

29. • First stage is to select the groups or clusters . • Then subsamples are taken in as many subsequent stages as necessary to obtain the desired sample. PCMS Peshawar Multistage sampling