Representations of data

Previously we have discussed about differential equations formulas and In today's session we are going to discuss about Representations of data which comes under cbse 12th syllabus, It means presenting the data in form of graphs, diagram, maps or chart besides the tabular form. In this type of representation of data, visualization is provided in forms of graphs and charts. There are some basic needs for the representation of data:

. Sometimes it is difficult to understand the descriptive data as it is not easy to draw the results.

. Easily draw the visual impression of the data

. Makes comparison easy

. Characteristics can be represented in a simplified way

. Some kind of patterns are made easy as population growth or distribution and density or age – sex composition , etc .

There are some rules that must be followed before designing the graphs,charts or diagrams

1. first of all a suitable graphical method is selected .

    
        Then after selecting the graphical method a scale is selected that is suitable to the data
        On the basis of Title,Index and Direction design must be followed.

There are several diagrams that are used for representing the data that can be categorized

in the following types :

. Some examples like Line graph, polygraph, histogram, pyramid and bar diagram etc. examples of One dimensional diagram.

. There are rectangular diagram and pie diagram examples of Two dimensional diagrams.

. Diagram as cube and spherical diagram examples of Three dimensional diagram.

Representation of data are done in many ways that are flow chart,line graphs,bar diagrams,pie diagrams , wind rose and star diagram etc .These are some examples of popular diagrams that are mostly used in representing the data.

Rainfall,Population growth,Temperature are examples of series of time, For representing the series of time e and series like birth rates and death rates etc are represented by drawing the Line graphs .

Two or more variables on a same diagram is represented by a Polygraph that is also a line graph ,that are shown by different line as example for showing the growth rate of different crops and These diagrams are also used for show the birth and death rates .

So there are different types of graphs and diagrams that are used for show the different type of representing data .In the next session we are going to discuss Sampling techniques.

In the next session we will discuss about online math tutor and You can visit our website for online tutoring for free.

Sampling techniques

Sampling techniques:

Previously we have discussed about definite integral examples and In today's session we are going to discuss about Sampling techniques which comes under cbse books for class 11,  Sampling is required when information is being processed for the transmission from one place to another place. The information is divided into samples and then the information is transmitted. It’s easy to remove noise or other factors from the samples in spite of the whole information directly.

If there are a lot items in a population set then the analysis process would be too costly and time consuming for that population. Like if the customer base id too large then  it would be too costly to determine the satisfaction level of each customer. The sampling process defines the same thing in short.

Sampling is the risk that it's not representative of the population from which it is made . Basically sampling  is the main step in analyzing any analytical process after that its not actually possible to remove errors.

The main processes for the sampling techniques are

·         Determine objectives and population then

·         Determining the sample size that would be created

·         Selection of the sampling method

·         Then the last step is to analyze the sampling errors regarding the projection or other

Sample size can be defined as

                                Sample size = reliability factor/Precision

There are several advantages of the sampling

·         The actual air sample can be collected without any breakthrough

·         No degradation problem of trapping material

·         Moisture has no effect on sampling

·         Duplicate analysis of the sample can be performed.

In mathematics it can be defined as to take a function f and recreate it with the help of only certain values.

Sampling techniques can be understood in probability or non probability preference. In probability method each member of the population has a non zero probability of being selected. This includes random, stratified and systemic sampling. In non probability method members are selected from the population in a random manner. It includes convent sampling, quota sampling, snowball sampling etc., techniques of sampling or methods for sampling are described below.

In Simple random sampling each member has an equal chance for being selected. It’s the purest method of sampling.

In systemic sampling every nth record is selected from the population.

Stratified sampling reduces the number of errors and used when one or more stratums have a low incidence relative to other.

Convenience sampling is used when inexpensive approximation of truth is required.

Judgment sampling is an extension of convenience sampling as the name indicates samples are made on the judgment basis.

Snowball sampling is used when desired sample characteristic is rare. It’s a difficult method and cost prohibitive too.

In the next session we are going to discuss Simple random sampling and You can visit our website for getting math help for free.