DEMOGRAPHY

DEMOGRAPHY

DR. MAHESWARI [email protected]

ETYMOLOGY• 1. DEMOS - People.

• 2. GRAPHO - To write.

• The word was coined by JOHN GRUNT

DEFINITION

• Demography is the "study of human populations in relation to the changes brought about by the interplay of births, deaths, and migration" PRESSAT

DEFINITION

• "Demography is the statistical description and analysis of human population". - WRONG

• Demography is the "statistical and mathematical study of the size, composition and spatial distribution of human populations, and of the changes over time, in these aspects through the operation of the five processess of fertility, mortality, marriage, migration and social mobility" - BOGUE

CONCEPT & SCOPE

• Demography is the branch of social size, structure, which deals with the study of size, structure and distribution of populations, along with the spatial and temporal changes in them in response to birth, migration, ageing and death.

DEMOGRAPHIC INDICATORS :(Eg)

• Crude Birth Rate. (CBR)

• General Fertitlity Rate. (GFR)

• Crude Death Rate. (CDR)

• Infant Mortality Rate. (IMR)

• Life expectancy. (LE)

• Total Fertility Rate. (TFR)

• Gross Reproduction Rate.(GRR)

• Net Reproduction Rate. (NRR)

SCOPE OF DEMOGRAPHY• Demography is the science of

population. In it's most general meaning, a population is a set of people who live in a specific land area : a commune, a district, a country or a continent,etc.

• A formal demography is concerned with the size, distribution, structure and changes of population

SIZE

• Is the number of units (inhabitants) in the population

DISTRIBUTION

• Is the arrangement of the population at a given time, geographically or among various types of residential areas.

STUCTURE• Is the distribution of characteristics such

as age, gender groups etc among the population.

• Additional characteristics of the uinits such as marital status, occupation educational level, ethnic characteristics, socio economic status etc.

CHANGE

• Is the increase or decrease of the total population or of the one of it's structural units.

NARROW SCOPE

• Population is constantly changing over time.

• The components of change in a population are births, deaths and migration.

• Thus one generation will be replaced by another younger generation by birth and death process.

• This is a natural change or demographic reproduction.

BROADER SCOPE• The broader scope of

demographic reproduction includes migration. It means the movement of people from place to place.

• Migration has great influence on population change.

• Within a country or an area, this movement does not affect the total size of the population.

• It changes the structure of the population and area as well as the living conditions of immigrants and out-migrants.

• This process may also influence the behaviour of the inhabitants, especially out migrants.

• Migrations have great influence on population change.

• A balancing equation of population change in time that involves the relationship between birth, death and migration is as follows.

• P1 = P0 + (B - D) + (I - O):• where, P1 & P0 : Population at the

ending & begening point.• B = # of Births in a period.• D = # of Deaths in a period.• I = # of In - migrants.• O = # 0f Out - migrants

DEMOGRAPHIC CYCLE

• Demography cycle has five stages:

• HIGH STATIONARY.

• EARLY EXPANDING.

• LATE EXPANDING.

• LOW STATIONARY.

• DECLINING.

DEMOGRAPHY CYCLE

DEMOGRAPHY CYCLE

HIGH STATIONARY.

EARLY EXPANDING.

LATE EXPANDING.

LOW STATIONARY.

DECLINING.

DEMOGRAPHY CYCLE

HIGH STATIONARY.

EARLY EXPANDING.

LATE EXPANDING.

LOW STATIONARY.

DECLINING.

High Birth RateHigh Death Rate

Unchanged Birth RateDecline Death Rate

Fall in Birth RateDeath Rate further

Low Birth RateLow Death Rate

Birth rate lower than Death Rate

STAGES OF DEMOGRAPHY CYCLE & COUNTRIES

High Stationary High High India (1920)

Early Expanding Unchanged Decline South Asia, Africa

Late Expanding Fall Further Decline

China, Singapore, India

Low Stationary Low Low Austria (1980-1985)

Declining Further lowers Unchanged Germany, Hungary

STAGE BIRTH RATE DEATH RATE COUNTRIES

DEMOGRAPHIC INDICATORS

• 1. Measurement of Mortality.

• 2. Measurement of Morbidity.

• 3. Measurement of disability.

• 4. Measurement of natality.

• 5. Measurement of the presence, absence or distribution of the characteristics or attributes of the disease.

• 6. Measurement of medical needs, health care facilities, utilization of health services and other health related events.

• 7. Measurement of the presence, absence or distributionof the environmental and other factors suspected of causing the disease.

• 8. Measurement of demographic variables.

TOOLS OF MEASUREMENT

• An epidemiologist usually expresses the health event as RATES, RATIOS or PROPOTION.

RATE• A rate measures the occurence

of some particular event in a population during a given period of time period.

• It is the statement of the risk of of developing a condition.

• It indicates the change in some event that takes place in a population over a period of time.

•

X 1000DEATH RATE = NUMBER OF DEATHS MID YEAR POP

X 1000

RATE : EXAMPLE

Weekly death rate = Deaths in a week x 52

Mid year populationx 1000

• A rate comprises the following elements.

• 1. Numerator.

• 2. Denominator.

• 3. Multiplier.

The time dimension is usually a calender year.

The rate is expresses per 1000 or some round figure.(selected according to convenience or convention to avoid fraction).

RATIO• Ratio expresses a relation in

size between two random quantities.

E.g., x : y (or) x/y.

• The numerator is not a component of the denominator.

• The numerator and denominator may involve an interval of time or may be simultaneous in time.

The number of children with scabies at a certain time.

The number of children with malnutrition at a certain time

PROPORTION• A Proportion is a ratio which

indicates the relation in magnitude of a part of the whole.

• The numerator is always included in the denominator.

• A Proportion is usually expressed as percentage.

Example

The number of children with scabies at a certain time.

The total number of children in the village at the same time

x 100

MEASUREMENTS OF MORTALITY

• Mortality refers to the number of deaths in a given time or a place or a proportion odf deaths in relation to a population.

• E.g., : 1. Crude Death Rate.

2. Infant Mortality Rate.

3. Maternal Mortality Rate

4. Life Expectancy.

MEASUREMENTS OF MORBIDITY

• It refers to diseases and illness, injuries and disabilities in a population.

• Data on the frequency and distribution of a disease helps in controlling its spread, and in some cases it may lead to the identification of cases.

Example

• 1. Case Rate : The case rate is the number of reported cases of a specific disease or illness per 100,000 population during a given year.

• 2. Case Fatality Rate : The Case Fatality Rate is the proportion of persons contacting a disease who die of that disease during a specified time period.

MEASUREMENT OF DISABILITY

• Dependancy Ratio : The ratio of the economically dependent part of the population to the productive part; arbitrarily defined as the ratio of the elderly ( ages 65 and older) plus the young (under age 15) to the population in the "working ages".

MEASUREMENTS OF NATALITY

• Natality in population ecology is the scientific term for Birth Rate.

• Along with mortality rate, natality rate is used to calculate the dynamics of a population.

• They are the key factors in determining whether a population is increasing, decreasing or staying the same in size.

• Natality is the greatest influence on a population’s increase.

• Natality is shown as a crude birth rate or specific birth rate. Crude Birth Rate is used when calculating population size (number of births per 1000 population/year).

• whereas Specific Birth Rate is used relative to a specific criterion such as age. By calculating specific birth rate, the results are seen in an age-specific schedule of births.

FORMULAS

BIRTH RATE (BR)

NUMBER IF LIVE BIRTHS DURING THE YEAR.

ESTIMATED MID YEAR POPULATION

X 1000BIRTH RATE =

GENERAL FERTILITY RATE (GFR)

NUMBER OF LIVE BIRTHS DURING A YEAR.

MID YEAR FEMALE POP (15-49) IN THE SAME YEAR

X 1000GFR =

GENERAL MARITAL FERTILITY RATE (GMFR)

NUMBER OF LIVE BIRTHS DURING A YEAR.

MID YEAR MARRIED FEMALE POP (15-49) YRS

GMFR = X 1000

AGE SPECIFIC FERTILITY RATE (ASFR)

NUMBER OF LIVE BIRTHS IN A PARTICULAR AGE GROUP.

MID YEAR POP OF THE

SAME AGE GROUP

ASFR = X 1000

AGE SPECIFIC MARITAL FERTILITY RATE (ASMFR)

NUMBER OF LIVE BIRTHS IN A PARTICULAR AGE GROUP.

MID YAER POP OF THE SAME AGE GROUP.

ASMFR = X 1000

TOTAL FERTILITY RATE (TFR)

• It is the average number of children a women can give birth throughout the reproductive period.

• It is represented by summing the age specific fertility rates for all ages; if 5 - year age groups are used, the sum of the rates is multiplied by 5.

TFR

45 - 49

15 - 19

1000

TFR =5 X ASFR∑

TOTAL MARITAL FERTILITY RATE (TMFR)

Average number of children that would be born to a married women if she experiences the current fertility pattern through her reproductive span.

TMFR

45 - 49

15 -19

1000

5 X ∑ ASMFRTMFR =

GROSS REPRODUCTION RATE (GFR)

• Average number of girls that would be borne to a women if she experiences the curent fertility pattern throught her reproductive span (15 - 49 years) having no mortality.

NET REPRODUCTIVE RATE (NRR)

• NRR is defined as the number of daughters a new borne girl will bear during her lifetime assuming fixed age-specific fertility and mortality rates.

• At presesnt in India NRR is about 1.5

• If NRR is < 1, then the reproductive performance of the population is said to be below replacement level.

MARRIAGE RATES

• The marriage rate (CRUDE MARRIAGE RATE) is the number of marriages per 1000 total population in a given year.

MARRIAGE RATE

NUMBER OF MARRIAGES IN THE YEAR

MID YEAR POPULATION

MR = X 1000

CHILD WOMAN RATIO

• Is the number of children 0 - 4 yrs of age per 1000 women of child bearing age.

PREGNANCY RATE.• It is the ratio of number of

pregnancies in a year to married women in the ages 15-49 yrs.

• The "number of pregnancies" includes all pregnancies, whether or had terminated as live births, stillbirths or abortions or had not yet terminated.

ABORTION RATE

• The annual number of all types of abortions, usually per 1000 women of child bearing age (15-19 yrs).

ABORTION RATIO

• This is calculated by dividing the number of abortions performed during a particular time period by the number of live births over the same period.

CRUDE DEATH RATE (CDR)

NUMBER OF DEATHS DURING A YEAR

MID YEAR POPULATION

CDR = X 1000

SPECIFIC DEATH RATE

NUMBER OF DEATHS FROM TB DURING A CALENDER YEAR.

MID YEAR POPULATIONSDR = X 1000

SPECIFIC DEATH RATE IN AGE GROUP 15-20 YRS

NUMBER OF DEATHS OF PERSONS AGED 15-20 DURING A CALENDER YEAR.

MID YEAR POPULATION OF PERSONS AGED 15-20

SPECIFIC DEATH RATE (15-20 YRS) = X 1000

DEATH RATE FOR JANUARY

DEATHS IN JANUARY X

12

MID YEAR POPULATION

DEATH RATE FOR JAN =

X 1000

WEEKLY DEATH RATE

DEATHS IN THE WEEK

MID YEAR POPULATION

WEEKLY DEATH RATE = X 1000

CASE FATALITY RATIO TOTAL NUMBER OF

DEATHS DUE TO A PARTICULAR DISEASE

TOTAL NUMBER OF CASES DUE TO THE SAME DISEASE

X 100CFR =

PROPORTIONAL MORTALITY RATIO

NUMBER OF DEATHS FROM THE SPECIFIC DISEASE IN A YEAR

TOTAL DEATHS FROM ALL CAUSES IN THAT YEAR

X 100PMR =

SURVIVAL RATE

TOTAL NUMBER OF PATIENTS ALIVE AFTER 5 YEARS

TOTAL NUMBER OF PATIENTS DIAGNOSED OR TREATED

SURVIVAL RATE =

X 100

STANDARDIZED MORTALITY RATIO

OBSERVED DEATHS

EXPECTED DEATHS

SMR = X 100

INFANT MORTALITY RATE (IMR)

NUMBER OF DEATHS OF CHILDREN LESS THAN 1 YEAR OF AGE IN A YEAR

NUMBER OF LIVE BIRTHS IN THE SAME YEAR

X 1000IMR =

ATTACK RATE

NUMBER OF NEW CASES OF A SPECIFIED DISEASE DURING A SPECIFIED TIME INTERVAL

TOTAL POPULATION AT RISK DURING THE SAME INTERVAL

X 100AR =

STILL BIRTH RATE (SBR)

FOETAL DEATHS WEIGHING OVER 1000g AT BIRTH DURING THE YEAR

TOTAL LIVE + STILL BIRTHS WEIGHING OVER 1000g AT BIRTH DURING THE YEAR

X 1000SBR =

PERINATAL MORTALITY RATE (PMR)

LATE FOETAL AND EARLY NEO NATAL DEATHS WEIGHING OVER 1000g AT BIRTH

TOTAL LIVE BIRTHS WEIGHING OVER 1000g AT BIRTH

X 1000PMR =

NEONATAL MORTALITY RATE (NMR)

NUMBER OF DEATHS OF CHILDREN UNDER 28 DAYS OF AGE IN A YEAR

TOTAL LIVE BIRTHS IN THE SAME YEAR

X 1000NMR =

POST NEONATAL MORTALITY RATE

NUMBER OF DEATHS OF CHILDREN BETWEEN 28 DAYS AND ONE YEAR OF AGE IN A GIVEN YEAR

TOTAL LIVE BIRTHS IN THE SAME YEAR

X 1000PNMR =

CHILD DEATH RATE

NUMBER OF DEATHS OF CHILDREN AGED 1-4 YEARS DURING A YEAR

TOTAL NUMBER OF CHILDREN AGED 1-4 YEARS AT THE MIDDLE OF THE YEAR

X 1000CDR =

CHILD MORTALITY RATE

NUMBER OF DEATHS OF CHILDREN LESS THAN 5 YEARS OF AGE IN A GIVEN YEAR

NUMBER OF LIVE BIRTHS IN THE SAME YEAR

X 1000CMR =

CHILD SURVIVAL INDEX

1000 - UNDER 5 MORTALITY RATE

10

MATERNAL MORTALITY RATIO

TOTAL NUMBER OF FEMALE DEATHS DUE TO COMPLICATIONS OF PREGNANCY, CHILDBIRTH OR WITHIN 42 DAYS OF DELIVERY FROM PUERPERAL CAUSES IN AN AREA DURING A GIVEN YEAR

TOTAL NUMBER OF LIVE BIRTHS IN THE SAME AREA AND YEAR

X 1000 / 100000MMR =

DISABILITY RATES• INDICATORS USED TO MEASURE

DISABILITY :

1. SULLIVAN INDEX

2. HEALTH ADJUSTED LIFE EXPECTANCY (HALE).

3. DISABILITY ADJUSTED LIFE YEAR

SULLIVAN INDEX

LIFE EXPECTANCY - (PROBABLE DURATION OF BED DISABILITY + INABILITY TO PERFORM MAJOR ACTIVITIES)

HEALTH ADJUSTED LIFE EXPECTANCY (HALE)

• Is an indicator of health which measures healthy life expectancy.

• HALE is equivalent to the number of years newborn child expected to live with full health.

DISABILITY ADJUSTED LIFE YEAR (DALE)

• Is used to express the years of life lost to premature death and years lived with disability for severity of disability.

• ONE DALY = ONE LOST YEAR OF HEALTHY LIFE

CASE RATE Number of reported

cases of a specific disease or illness

100,000 population during a given year

EMIGRATION RATE

NUMBER OF EMIGRANTS DEPARTING AN AREA OF ORIGIN

1000 POPULATION AT THAT AREA OF ORIGIN IN A GIVEN YEAR

NET EMIGRATION RATE

The net effect of immigration and emigration on an area's population (increase or decrease) is refered to as net migration.

The net migration shows the net effect of immigration & emigration on an area's population of the area in a given year.

GROWTH RATE The growth rate is the rate at which a

population is increasing (or decreasing) in a given year due to natural increase and net migration, expressed as a percentage of the base population.

• The growth rate takes in to account all components of population growth: births, deaths and migration.

LIFE EXPECTANCY

The number of years which an individual at a given age could expect to live, at present mortality levels

USES OF DEMOGRAPHIC DATA

• Analysis patterns and trends related to human religion, nationality, education and ethnicity.

• Estimates are reliable standards for judging the accuracy of the census information gathered at any time.

• Estimates size and flow of populations of workers; in population ecology, the focus is on birth, death and movement of firms and institutional forms.

• Uses administrative records to develop an independent estimate of the population.

• Provides insight into the links between these characteristics and cultural, economic, geographic and other social attributes present in a given area.

• Demographic analysis is a powerful tool that can explain a number of sociological phenomena.

• Used to estabilish the percentage of the total population involved in a particular resource use activity, such as fishing or tourism.

• Apply to whole societies or to groups defined by criteria such as education, nationality, religion and ethnicity.

• Analyzes the relationship between economic, social, cultural and biological proceses influencing a population.

• Time and age have special relationships in popultion studies, from which cross sectional and cohort analysis are developed.

• Relates to whole societies or to a smaller groups defined bycriteria such as education, religion or ethnicity.

• Develops targeted outreach and training activities for local communities.

HEALTH INFORMATION SYSTEM (HIS)

DEFINITION

• Heath Information or Medical Statistics refers to any quantifyable and non quantifiable information that can be used by health decision makers and clinicians to better understand disease process and health care issues, and to prevent, diagnose or treat health problems.

• Medical statistics deals with the application of bio statistics to medicine and the health sciences, including epidemiology, public health, forensic medicine and clinical research.

• A HIS system refers to inter related component parts for acquiring and analysing data and providing information for the management of a health programme or system and for monitoring health services

SOURCES OF HEALTH INFORMATION

• The main population based sources of health information are as follows :

• 1. Census.• 2. Household Surveys.• 3. Sample Registration System.• 4. Notification of Disesase.• 5. Hospital Records.

CENSUS

HOUSEHOLD SURVEY

NOTIFICATION OF DISEASE

• 6. Disease Registers.• 7. Record Linkage.• 8. Epidemiological Surveillence.• 9. Other Health Service Records.• 10. Environmental Health Data.• 11. Population Surveys.• 12. Other routine statistics related

to health.• 13. Non quantifiable information.

DISEASE REGISTERS

EPIDEMIOLOGICAL SURVEILLENCE

POPULATION SURVEY

ENVIRONMENTAL HEALTH DATA

RECORD LINKAGE

SOURCES OF HEALTH INFORMATION

METHODS OF DATA COLLECTION

• There are two methods of data collection:

1. DIRECT METHOD.

2. INDIRECT METHOD.

DIRECT METHOD

1. VITAL STATISTICS REGISTRIES:

A. BIRTHS & DEATHS.

B. CENSUS.

C. LEGAL STATUS (Marriage, divorce and migration)

CENSUS

• Census is taken typically every 10 yrs.

• Census are also used as direct source of information about fertility and mortality.

• The census is commonly performed by a government agency and the methodology used is the individual or household enumeration.

• In India the first census was taken in the year 1901 on March 1st.

• The latest census was taken in the year 2001 on March 1st.

The purposes for census include :

1. As a basis for taxation.

2. As a basis for political representation.

INDIRECT METHOD

• THERE ARE SEVERAL METHODS AS FOLLOWS:

• 1. SISTER METHOD: The survey researchers ask women how many of their sisters have died or had children and at what age.

• 2. OTHER INDIRECT METHOD include asking people about siblings, parents and children.

• 3. RESEARCH SURVEY.

• 4. NATIONAL SAMPLE SURVEY

• 5. SAMPLE REGISTRATION SURVEY.

• 6. DEMOGRAPHIC METHODS :

• MODELS OF MORTALITY - Life table, Gompertz models, hazards models, multiple decrement life tables, Brass relational logits.

MODELS OF FERTILITY - Hernes model, Coal-Trussell models, parity progression ratios.

• MODELS OF MARRIAGE : Singulate Mean at marriage, Page model.

• MODELS OF DISABILITY : SAULLIVAN'S METHOD, MULTISTATE LIFE TABLES.

• POPULATION PROJECTIONS: Lee Carter, the Leslie Matrix.

• MODEL OF MIGRATION : Keyfitz.

APPLICATION-METHODS OF DATA COLLECTION

I. PRIMARY DATA collection is done by the individual using:

1. Interviews.2. Observation.3. Questionnaires.4. Diaries.5. Critical incidents.

• SECONDARY DATA collection is done by :

1.Census.

2. National Survey.

3. Registration of vital events.

4. Demographic studies.

5. Records.

RECORDS

NATIONAL SURVEY

NATIONAL SAMPLE SURVEY

INTERVIEWS• Interviews are undertaken on

personal, one to one basis or in a group.The advantages of interview method are as follows.

1.It is the best means to collect an indepth information.

2.The feedback and response rate is good.

3.The information is recorded immediately and complete.

4. Help can be provided immediately.

DISADVANTAGES OF INTERVIEW

1. It is expensive and time consuming.

2. Training is required in case of employing many interviewers.

3. Pre fixed questionnaire are required.

TYPES OF INTERVIEWS• An interview can be of three types:

1. STRUCTURED.

2. SEMI STRUCTURED

3. UNSTRUCTURED.

OBSERVATION• Is a method to record behavioural

pattern of people in a systematic manner.

• The methods of observation include: structured, un structured, natural, personal, mechanical, participant or non participant observations.

• Observation method provides information on what is actually observed.

• Bias in observation method can be eliminated by two observers.

• Hence this method has limitations in eliciting accurate information.

QUESTIONNAIRES

• Questionnaire is a common method of data collection.

• It takes time and expertise to prepare a structured questionnaire.

• The questionnaire can be used to interview for a direct data collection or a telephonic survey could be conducted.

• It can be posted, emailed or faxed.

• The main advantage of this method is that there is no bias.

• The use of questionnaire is simple but requires a certain level of education and skill from respondents.

DIARIES• Diaries are used to record data

obtained from the individuals.

• The data expressed in the diaries are an indepth information and can be used for reseaech purposes.

CRITICAL INCIDENTS

• The critical incidents relating to health - illness event is recorded and used for arriving desicions and policies regarding health matters.

II.SECONDARY DATA

• The secondary data is collected indirectly (not from inviduals) from other sources such as hospital records, census data etc.

SOURCES OF DEMOGRAHIC DATA

• Census.

• Natioal Survey.

• Registration of vital events.

• Demographic studies.

• Records.

SURVEY

CENSUS• Census is the direct method of

collection of demographic data.

• Census is conducted by the government every 10 yrs.

• Census is an attempt to contact every member of the population in a country.

• Census not only provides information regarding the number of people, but other relevant information (age, gender, marital status, occupation, education, employment status, migration, language, religion etc.)

• A census covers social & economic aspects of a population.

• It is conducted at the end of first quarter of each decade.

• The census commisioner of India guides, operates, and directs the census.

REGISTRATION OF VITAL EVENTS

• Registration of vital events is the basis of vital statistics.

• Vital events refers to births, death, migration, marriages, divorces, foetal deaths are registration in India.

• In 1873, Govt of India passed the Birth, Deaths & Marriage Registration Act.

• Indian states such as Karnataka, Tamil Nadu etc have passed their own acrs related to registration of vital events.

• The main drawback in this registration process is that it has the provision only for voluntary registration.

• So data is not accurate and complete as people do not voluntarily get the birth, death or marriages registered.

• The data tends to be unreliable.

• The other reasons for incompleteness include :

1. Illiteracy.

2. Ignorance.

3. Lack of concern.

4. Lack of motivation.

5. Lack of uniformity.

6. Multiple registration agencies.

NATIONAL SURVEY

• National Survey refers to the survey conducted at central level to collect the information related to population from various states.

DEMOGRAPHIC STUDIES

• Studies conducted on demography also provide data regarding the population's education, occupation etc.

• The demographic studies provide information about the latest demographic changes occuring from time to time.

RECORDS• Records available in hospitals

constitute the basic and primary source of information about births and deaths due to specific illness.

• Hospital data provides the numerator. (not the denominator & hence is incomplete)

ANALYSIS & INTERPRETATION OF DATA

• The data thus collected should be aranged in tables, charts, diagrams, graphs, picture & curves to stress important points.

• The data presented should be based on the principles designed to meet the criteria.

CHARACTERISTICS OF A TABLE

• A table has a title, table number, rows, coloums, row head, coloum head.

• The data is presented as discrete variables or as class intervals or according to chronological order or in alphabetical order.

CHARTS• The data collected could be

represented in the form of a chart.

• The data contained in a chart is more easy to understand and retained easily than a table.

TYPES OF CHARTS :1. BAR CHARTS. (simple. Compound,

Histogram)

2. LINE DIAGRAMS.

3. PIE CHARTS.

4. PICTOGRAM.

6. STATISTICAL MAP.

7. STATISTICAL AVERAGES & DISPERSION OF MEASURES OF VARIATION

BAR CHART

• Bar charts are easy to prepare.

• They enable values to be compared at a glance.

• In bar charts, bars proportional to the magnitude are presented.

TYPES OF BAR CHARTS

1. Simple Bar Chart.

2. Component Bar Chart.

3. Histogram.

SIMPLE CHART

• The simple bar chart represents observations proportional to the magnitude.

• 2. The bars can be either vertical or horizontal.

COMPONENT BAR CHART1. The component bar chart represents many components.

2. The representation could be either as vertical or as horizontal bars.

HISTOGRAM1.Histogram is a pictorical diagram which consists of series of blocks.

2.If the mid point of histogrms blocks is joined, then a line with fluctuation is seen

3.frequency polygon is obtained by joining the mid points of histogram blocks.

LINE DIAGRAM• Line Diagram show the trend of

events occuring over a pasage of time in continuation such as rise or fall of AIDS cases over a period of 5 years.

• i.e. during the year 2000,2001,2002,2003 & 2004,

LINE DIAGRAM

PIE CHART• Pie charts are diagramatically

represenred in circles with the radius "O". and at radius angle 360 degree.

• The area of the circle in the form of segment which depends upon the angle.

• These segments within the circle are comparable.

• The segments are indicated in percentages.

• To find out the angle at radius "O" from the data, can be calculated using a formula.

Degree to be presented =

Given percentage

100

x 360

Example• 75% of people are literate & 25% of

people are illiterate.

• Angle for literate = 75 /100 x 360 = 270.

• Angle for illiterate = 25 / 100 x 360 = 90.

REPRESENTATION

90

27075% LITERATE

25% ILLITERATE

PIE CHART

TYPES OF PIE CHART

PICTOGRAM

• In pictogram, small pictures or symbols are used to present the data.

PICTOGRAM

HUMAN PICTOGRAM

STATISTICAL MAP

• Statistical maps are used to present the data of different sizes.

• The data are presented in form of shaded maps or dot maps.

STATISTICAL MAP

• When there is a need to indicate the relationship of two variables, scattered diagrams are used.

• A linear relationship is evident if the dots are near or around a straight line.

SCATERRED DIAGRAM

STATISTICAL AVERAGES

• Statistical averages refers to the values in distribution, around which other values are distributed such as mean, median & mode.

• These are commonly used averages which provide an information of about central value.

STATISTICAL AVERAGES

DISPERSION OF MEASURES OF VARIATIONS

NORMAL DISTRIBUTION CURVE

• Normal distribution curve is used to represent the values for a very large number of people after creating narrow class intervals with frequency distribution.

• The shape of the curve is based on mean and standard deviation.

NORMAL DISTRIBUTION CURVE

CHI SQUARE TEST

• Chi square test is used to test the significance of difference between two proportions.

CHI SQUARE TEST

CORRELATION• A correlation test is

used to find out the relationship between two variables.

• E.g., Relationship between level of knowledge and practice.

REGRESSION TEST

• Regression test is used to find out the estimated value of one variable from value of another.

INTERPRETATION OF DATA

• The data collected is analysed and interpreted.

• The interpretations are then generalized to public.

• The values interpreted should be in simple so as to make it understandable.

• While interpreting, the maximun & minimum values should be shown so as to have an estimastion in between.

• The data represented shoul be presentes as rates, ratios, proportions, percentage, mean, median,mode and normal curve.

• The demographic data are usually analysed and interpreted by tables, charts, diagrams, pie charts, pictogram etc.

THANK YOU

DEMOGRAPHY

Health & Medicine

Transcript of DEMOGRAPHY