Introduction to basic concepts of statistics

Introduction to basic concepts of statistics

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  Presented By AFSHEEN AFFAN
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   Statistics isthe science of collecting, organizing, presenting, analyzing and interpreting the data to assist in making more effective decisions. OR  A body of methods dealing with the collection, description, analysis and interpretation of information that can be given in numerical form.
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   Statistics areaggregate of facts  Statistics are numerically expressed  Statistics are affected by multiplicity of causes  Statistics are according to reasonable standard of accuracy  Statistics are collected in a systematic manner  Statistics are collected for a pre- determined purpose
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   Statistics arecollected in a systematic manner  Statistics are collected for a pre- determined purpose  Statistics must be comparable to each other
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  “Statistics are aggregateof facts, affected to a marked extent by a multiplicity of causes, numerically expressed, enumerated or estimated according to a reasonable standard of accuracy, collected in a systematic manner for a pre determined purpose and placed in relation to each other”
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   Theoretical Statistics( formula and rules)  Descriptive Statistics ( numerical, graphical, tabular forms)  Inferential Statistics ( drawing conclusion)  Applied Statistics ( application of statistics for policy purpose)
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   It presentsfacts in a numerical form  Statistics simplifies complex mass of data  Comparison of data becomes easier  Statistics studies relationship among different facts  Statistics studies changes in a variable  Statistics helps forecasting
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   Business andEconomics  Banks  Insurance  Sciences
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   OBSERVATION  Anythingthat can be measured or observed is called an observation  DATA  Numbers or measurements that are collected as a result of observation  POPULATION  A population is the set of all units of interest in a particular study.
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   SAMPLE  Asample is a subset of data selected from population.  PARAMETER  A parameter is the value associated with population.  STATISTIC  A statistic is a value computed from a sample.
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   Variable  Avariable is a phenomenon that may vary from one individual or object to another e.g. height of students in your class etc.  Constant  A quantity which is fixed is called a constant e.g. no. of days in a week, no. of months in a year etc.
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   Quantitative Data Quantitative data are observations measured on numerical scale e.g. Data of heights, weights, marks etc.  Qualitative Data  Qualitative data are observations that are non-numerical e.g. data of beauty, intelligence etc. we don’t have scale to measure them.
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   Discrete Data Data whose possible values are countable is called discrete data e.g. data of prices, incomes etc.  Continuous Data  Data whose possible values are uncountable and which may assume any value in an interval is called continuous data e.g. record of temperature etc.
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   Quantitative variable When the variable to be studied can be reported numerically, the variable is called quantitative variable e.g. marks in test of statistics etc.  Qualitative variable  When the characteristic being studied can not be recorded in numerical form, it is called a qualitative variable e.g. intelligence, gender etc.
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   Discrete Variables A discrete variable is one that can assume only certain values within an interval e.g. price of rice etc.  Continuous Variable  A continuous variable can take on all possible values within a specified range e.g. speedometer of car, temperature etc.
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   Independent Variable A variable is called independent variable if it is not influenced by any other variable e.g. price of potatoes.  Dependent variable  A variable that is being predicted or estimated is called dependent variable e.g. quantity demanded of potatoes is dependent variable because it depends on price of potatoes.
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   Primary Data( first hand data)  Direct personal observation  Indirect personal investigation  Questionnaire method  Collection through enumerators  Collection through local sources  Secondary Data ( processed data)  Official statistics  Semi official
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   Biased Error Unbiased Error
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   Accuracy  SignificantFigures  Rounding Off Figures  Multiplication  Inequalities  Approximation  Limits  Modulus  Factorials
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   The operationof summation is symbolized by the use of greek capital letter Σ . σ𝑖=1 𝑛 𝑋𝑖 = 𝑋1 + 𝑋2 + 𝑋3 + ⋯ + 𝑋𝑛 Some other notations ❑ Σ𝑋2 → means square each value of X, and then sum ❑ Σ𝑋 2 → means sum the values of X and then square the total ❑ Σ 𝑋 − 3 → means subtract 3 from each value of X , and then sum ❑ Σ𝑋𝑌 → means multiply each value of X and Y and then add
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  THE END