Statistic is a collection of methods for planning experiments and then organising, summarising, presenting, analysing, interpreting and drawing conclusion based on the data. The term statistics has been defined in two ways:
- Sungular sense,
- Plural sense.
In the singular sense statistics may be defined as the science of collection, presentation, analysis, and interpretation of data. In plural sense, statistics may be defined as the aggregate of the facts affected to the market extent by multiplication of causes, numerically expressed, and estimated according to reasonable standard of accuracy, collected in a systematic manner for predetermined purpose and placed in relation to each other.
Statistics may be classified into two types:
- Theoretical Statistics or Mathematical Statistics
- Apploed Statistics
Theoretical or mathematical statistics:
Mathematical statistics deals with the development of statisti....
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Statistic is a collection of methods for planning experiments and then organising, summarising, presenting, analysing, interpreting and drawing conclusion based on the data. The term statistics has been defined in two ways:
- Sungular sense,
- Plural sense.
In the singular sense statistics may be defined as the science of collection, presentation, analysis, and interpretation of data. In plural sense, statistics may be defined as the aggregate of the facts affected to the market extent by multiplication of causes, numerically expressed, and estimated according to reasonable standard of accuracy, collected in a systematic manner for predetermined purpose and placed in relation to each other.
Statistics may be classified into two types:
- Theoretical Statistics or Mathematical Statistics
- Apploed Statistics
Theoretical or mathematical statistics:
Mathematical statistics deals with the development of statistical theory and methods based on certain principles and mathematics. It is subdivided into two parts:
- Descriptive statistics and
- Inferential statistics
Descriptive Statistics:
The branch of statistics devoted to the summarisation and description of data (population or sample) is called descriptive statistics.
Inferential Statistics:
The branch of statistics concerned with using sample data to make inference about the population of data is called inferential statistics.
Applied Statistics:
It deals with application of theoretical or mathematical statistical methods to data in the different areas. The statistical tools and methods are used in order to save many practical problems in diversified area. It is also used in decision making process.
Uses and Importance of Statistics in the field of Engineering:
Statistic has various engineering application in testing materials, performance test of system, robotic and automatization, control of production process and so on. It has great importance in different field of Engineering such as:
- Design of experiments uses Statistical Techniques to test and construct models of Engineering components and Systems.
- Quality control and process control use statistics as a tool to manage conformance to specifications of manufacturing process and their products.
- Time and methods engineering use statistics to study repeated operation in manufacturing in order to set standards and find optimum manufacturing procedures.
- Reliability engineering uses statistics to measure the ability of a system to perform for its intended function (and time ) as tools for improving performance.
- Probabilistic design uses statistic in the use of probability in product and system design.
- To workout the time a job will take and how many people are needed.
Functions of Statistics:
Statistics has been playing a vital role in almost every field of human beings. Some important functions are listed below:
- Statistics simplified complexity.
- To represent facts from numerical figures in a definite form.
- To help in classification of data according to the nature of data.
- To help in formulating policies.
- To determine the relationship between different phenomena.
- To help in predicting future trends.
- To formulate and test hypothesis.
- To have an idea about occurrences and non occurrence of certain events.
- To draw valid inferences or conclusions.
Limitations of Statistics:
- Statistic deal with aggregates only. It does not study individuals. An individual, to an statistician has no significance except the fact that it is a part of the aggregate.
- Statistics does not study the qualitative phenomenon. It is only concerned with quantitative data.
- Statistical laws are not exact. Since these laws are probabilistic in nature, so they do not hold well in every case. It is also said that statistic itself is not an absolute measure. It provides precise results minimising error as much as possible.
- Statistic is only means.
- Statistic is liable to be misused statistic neither proves nor disproves anything. The use of statistical tools by inexperienced untrained person might lead to very fallacious conclusions. In words of W.I King, 'statistics are like clay of which you can make a god or a devil as you please. Therefore statistical methods are the most dangerous tools in the hand of the inexport . So only the expert of statistician can handle statistical data properly.
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