Statistics

Statistics

Statistics is the study of the collection, analysis, interpretation, presentation, and organization of data. In other words, it is a mathematical discipline to collect, summarize data.

According to Merriam-Webster dictionary, statistics is defined as “classified facts representing the conditions of a people in a state – especially the facts that can be stated in numbers or any other tabular or classified arrangement”.

According to statistician Sir Arthur Lyon Bowley, statistics is defined as “Numerical statements of facts in any department of inquiry placed in relation to each other”.

Mathematical Statistics

Mathematical statistics is the application of Mathematics to Statistics, which was originally conceived as the science of the state — the collection and analysis of facts about a country: its economy, and, military, population, and so forth.

Mathematical techniques used for this include mathematical analysis, linear algebra, stochastic analysis, differential equation and measure-theoretic probability theory.

Scope

Statistics is used in many sectors such as psychology, geology, sociology, weather forecasting, probability and much more. The goal of statistics is to gain understanding from data it focuses on applications and hence, it is distinctively considered as a Mathematical science.

Methods

The methods involve collecting, summarizing, analyzing, and interpreting variable numerical data. Here are some of the methods provided below.

  • Data collection
  • Data summarization
  • Statistical analysis

Data

Data is a collection of facts, such as numbers, words, measurements, observations etc.

Types of Data-

  1. Qualitative data- it is descriptive data.
    • Example- She can run fast, He is thin.
  2. Quantitative data- it is numerical information.
    • Example- An Octopus is an Eight legged creature.

Types of quantitative data

  1. Discrete data- has a particular fixed value. It can be counted
  2. Continuous data- is not fixed but has a range of data. It can be measured.

Representation of Data-

Statistics- Bar graph Bar Graph
A Bar Graph represents grouped data with rectangular bars with lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally.
Statistics-Pie chart Pie Chart
A type of graph in which a circle is divided into Sectors that each represent a proportion of the whole.
Statistics-Line graph Line graph
The line chart is represented by a series of data-points connected with a straight line
The series of data points are called ‘markers.’
Statistics-Pictograph Pictograph
A pictorial symbol for a word or phrase, i.e. showing data with the help of pictures. Such as Apple, Banana & Cherry can have different numbers, it is just a representation of data.
Statistics- Histogram Histogram
A diagram consisting of rectangles whose area is proportional to the frequency of a variable and whose width is equal to the class interval.
Frequency distribution in Statistics Frequency Distribution
The frequency of a data value is often represented by “f.” A frequency table is constructed by arranging collected data values in ascending order of magnitude with their corresponding frequencies.

Formulas used

Sample Mean (\(\bar{x}\)) \(\frac{\sum x}{n}\)
Population Mean (\(\mu\)) \(\frac{\sum x}{N}\)
Sample Standard Deviation (s) \(\sqrt{\frac{\sum (x-\bar{x})^{2} }{n-1}}\)
Population Standard Deviation (\(\sigma\)) \(\sigma = \sqrt{\frac{(x-\mu )^{2}}{N}}\)
Sample Variance (\(s^{2}\)) \(s^{2} = \frac{\sum (x_{i}-\bar{x})}{n-1}\)
Population Variance (\(\sigma ^{2}\)) \(\sigma ^{2} = \frac{\sum (x_{i} – \bar{x})}{N}\)
Range (R) Largest data value – smallest data value

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Types of Statistics

Basically, there are two types of statistics.

  • Descriptive Statistics
  • Inferential Statistics

In case of descriptive statistics, the data or collection of data is described in a summary. But in the case of inferential stats, it is used to explain the descriptive one. Both these types have been used in large scale.

There is one more type of statistics, where descriptive is transitioned into inferential stats.

Application

  • Some of the application of statistic are given below:
  • Applied statistics, theoretical statistics and mathematical statistics
  • Machine learning and data mining
  • Statistics in society
  • Statistical computing
  • Statistics applied to Mathematics or the arts

Statistics Examples

Some of the real life examples of statistics are:

  • To find the mean of the marks obtained by each student in the class whose strength is 50. The average value here is the statistics of the marks obtained.
  • Suppose you need to find how many members are employed in a city. But since the city is populated with 15 lacs people, hence we will take a survey here for 1000 people (sample). Based on that we will create the data, which is the statistic.

Hope this detailed discussion and formulas on statistics will help you to solve problems easier and faster. Learn more Maths concepts at BYJU’S with the help of interactive videos.

Frequently Asked Questions on Statistics

What exactly is statistics?

Statistics is a branch that deals with the study of the collection, analysis, interpretation, organisation, and presentation of data. Mathematically, statistics is defined as the set of equations, which are used to analyse the things.

What are the two types of statistics?

The two different types of statistics used for analysing the data are:

  • Descriptive Statistics: It summarizes the data form the sample using indexes
  • Inferential Statistics: It draws the conclusion from the data which are subjected to the random variation

How is statistics applicable in Maths?

Statistics is a part of Applied Mathematics, that uses probability theory to generalize the collected sample data. It helps to characterize the likelihood where the generalizations of data are true. This is known as statistical inference.

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