1. Dr Zia-Ul-Ain Sabiha

2.  At the end of this session the students will be able to  Define Statistics  Differentiate between Descriptive Statistics and Inferential Statistics  Define Biostatistics  Discuss the Uses of Biostatistics  9/6/20152CHS deptt

3.  Define  Data  Sample and Population  Variables  Measurement variables  Types of Data  Exercises to summarize the lecture. 9/6/20153CHS deptt

4.  Statistics is science of conducting studies to collect,organize, summarize, analyze, and draw conclusions from the data. 9/6/20154CHS deptt

5.  A subject that deals with the collection, compilation, presentation, analysis and presentation of data.  Drawing inferences about a body of data when only a part of the data is observed.  Scientific study of numerical data based on natural phenomenon 9/6/20155CHS deptt

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7.  Descriptive Statistics  Consists of the collection, organization, summarization, and presentation of data.  Inferential statistics  consists of generalizing from samples to populations,performing estimations and hypothesis tests, determining relationships among variables and making predictions.  It uses probability i,e., the chance of event occuring 9/6/20157CHS deptt

8.  The origin of descriptive Statistics can be traced to data collection methods used in censuses taken by the Babylonians and Egyptians between 4500 and 3000 B.C.  In addition the Roman Emperor Augustus (27 B.C-A.D. 17) conducted surveys on births and deaths of the citizens of the empire, as well as the number of livestock each owned and the crops each citizen harvested yearly. 9/6/20158CHS deptt

9.  Inferential Statistics originated in the 1600s, when John Graunt published his book on population growth, Natural and Political Observations Made upon the Bills of Mortality.  About the same time,another mathematician/astronomer, Edmund Hally, published the first complete mortality tables.( insurance companies use mortality tables to determine life insurance rates). 9/6/20159CHS deptt

10.  Application of Statistical methods to the solution of biological problems 9/6/201510CHS deptt

11.  In Epidemiology  In demography  Morbidity and mortality rates and ratios.  Collection and registration of vital events.(Births,Deaths, Marriages and divorces)  Sampling for different statistical procedures.  To know the frequency of different diseases and biological problems.  For interpretation of data.  To know about association and causation of diseases. 9/6/201511CHS deptt

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13.  Record of observations  Facts and figures  Any piece of information Information When data is processed and made meaningful 9/6/201513CHS deptt

14.  Data are numbers which can be measured or can be obtained by counting. Biostatistics is concerned with the interpretation of the data and the communication of information about the data. 9/6/2015CHS deptt14

15. Data are obtained from  Analysis of records  Surveys  Counting  Experiments  Reports 9/6/2015CHS deptt15

16.  A characteristics,object and property that assumes different numerical value for each possible outcome/individual/element of the population or sample is called a variable.  The actual property measured on the individual selected for sample.  E.g. Height,weight,temprature,age,smoking, 9/6/201516CHS deptt

17. A random variable is one that cannot be predicted in advance because it arises by chance. Observations or measurements are used to obtain the value of a random variable. Random variables may be discrete or continuous. Discrete random variable A discrete random variable has gaps or interruptions in the values that it can have. The values may be whole numbers or have spaces between them. Continuous random variable A continuous random variable does not have gaps in the values it can assume. Its properties are like the real numbers. 9/6/2015CHS deptt17

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20.  Independent and dependent  Independent variables are presumed causes and dependent variables are presumed effects. 9/6/201520CHS deptt

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22.  The whole set of things about which we want to know.  In biostatistics population can be human beings, ECG machines, Paracetamol tablets.  A population is the collection or set of all of the values that a variable may have. A sample is a part of a population. 9/6/201522CHS deptt

23.  A part or subset of population for actual study. OR  A collection of individual observations selected by a specific procedure from a population. 9/6/201523CHS deptt

24.  Measurement variable  Continuous variables  Discontinuous variables or discrete variable  Ranked variables  Categorical variable 9/6/201524CHS deptt

25.  Continuous variables  Which at least theoretically can assume an infinite number of values between any two points. e. g length,period of time,height, weight, age,  Discrete, Discontinuous variables  That has only certain fixed numerical values with no intermediate values possible in between. e.g. number of offsprings, no. of teeth, no. of glands. 9/6/201525CHS deptt

26.  Which cannot be measured but ranked or ordered.e.g. rank order of pupa emergence or seed germination. 9/6/201526CHS deptt

27.  The characteristics that are qualitative in character and hence cannot be expressed numerically( or quantitatively) are called descriptive characteristics or attributes.  The sex of a newly born baby.  Eye color of a girl.  The language of a Arabian visitor.  The style of a speaker 9/6/201527CHS deptt

28.  Data consists of variables.  There are four scales of measurement  Nominal(category)  Ordinal(category)  Interval(quantity,continuous )  Ratio(quantity, continuous) 9/6/201528CHS deptt

29. ScaleCharacteristic questionExample NominalIs A different than B?Marital status Eye color Gender Religious affiliations Race ordinalIs A bigger than B?Stage of disease Severity of pain Level of satisfaction IntervalBy how many units do A and B differs? Temperature SAT score RatioHow many times bigger than B is A?Distance Length Time until death Weight 9/6/2015CHS deptt29

30.  Classifies persons or things based on the characteristic being assessed  No information is given on quantity or amount  A variable without an intrinsic order.  Examples  Male or female  Nationality (American, Mexican, Pakistani)  Favorite pet( dog, cat, fish, snake) 9/6/201530CHS deptt

31.  Classifies persons or things based on the characteristic being assessed  Can be placed in meaningful order,  Indicates “more than” or “less than”  Does not indicate how much more or how much less than  Example: Rating a student’s performance as ‘good’, ‘fair’, ‘poor’ 9/6/201531CHS deptt

32.  Classifies persons or things based on the characteristic being assessed  Indicates “more than” or “less than ” and the magnitude of the observation  There is no true zero or meaningful zero.  Examples  Temperature  Year of birth  Date of diagnosis 9/6/201532CHS deptt

33.  Classifies persons or things based on the characteristic being assessed  Indicates “more than” or “less than” and the magnitude of the observation  Zero point is indicated  True ratios exist when the same variable is measured on the different members f the population.  Examples:  Height  Weight  Age 9/6/201533CHS deptt

34.  Date of diagnosis  Town of residence  Age (years)  Sex 9/6/201534CHS deptt

35.  Date of diagnosis: Interval  Town of residence: Nominal  Age (years): Ratio  Sex : Nominal 9/6/201535CHS deptt

36.  Name the scale of measurement for each variable below:  Year of birth:  Marital status of a women:  Identification number of study participants:  Class rank:  Length of infants at ANC clinic: 9/6/201536CHS deptt

37.  Year of birth: Interval  Marital status of a women: Nominal  Identification number : Nominal  Class rank: Ordinal  Length/Height of infants at ANC clinic: Ratio 9/6/201537CHS deptt

38.  Identify whether the following data is discrete or continuous  Distance from primary health center to reference lab:  Number of times a child under 5 has experienced fever in the last month:  Number of fatal accidents on a road over the past year:  Weight gained or lost by a 9 month old in the past 3 months: 9/6/201538CHS deptt

39.  Distance from primary health center to reference lab: Continuous  Number of times a child under 5 has experienced fever in the last month: Discrete  Number of fatal accidents on a road over the past year: Discrete  Weight gained or lost by a 9 month old in the past 3 months: Continuous 9/6/201539CHS deptt

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