Transcript for:
Sampling Methods in Research

this short animated video explains the concept of  sampling and the different types of sampling that   are used in research so don't go anywhere else  just sit back relax and enjoy the video hello   and welcome to yet another video series from  distributed learning your one-stop solution for   all your learning needs so before we understand  sampling and its type let us first understand the   difference between these two terms population and  sample the sample is a small group selected from   population to represent the entire population so  when you conduct research about a group of people   it is almost impossible to collect data from  every person in that group instead you select   a sample and the sample is a group of individuals  who will actually participate in the research and   will represent the entire population sample is  basically a subset of population that is based   on the fact that it is drawn from the population  now what is population operation is a group from   which the sample is drawn exact population  will depend upon the scope of the study let   us understand with some real-life examples here  millions around the world are infected because   of this covert in nineteen and many companies are  in progress of developing vaccines and then in the   process they are also doing some clinical trials  so they will select a small portion of people from   different background probably age gender and those  who are infected with covered 19 as a sample and   then will perform a study on these individual  because it's not possible to conduct tests on   millions of individuals at one time so that is  a difference between the population and sample   now it understand what is sampling sampling  is a method that allows researchers to infer   information about population based on the results  from sample without having to investigate every   individual so reducing the number of individuals  in a study reduces your cost You've workload and   may make it easier to obtain a high-quality  information to draw a valid conclusion from   your result you have to carefully decide how will  you select a sample that is the representative of   the group as a whole so broadly speaking they are  two different categories of sampling one is the   probability sampling and next is a nonprobability  sampling probability sampling so probability   sampling is based on the fact that every member  of population has known an equal chance of being   selected this method is based on the theory of  probability for example when you flip a coin   there are a 50/50 chance of getting a head or  tail and if you flip a coin once more again the   chance of getting a head or tail is 1550 even if  you flip a coin a hundred times the next time when   you flip a coin the chance of getting a head or  tail will still be 50 or 50 and in that case you   still want to investigate the coin and why it  is coming up head or tail every time the bottom   line of random selection process here is that  equal probability and the independence of events   when we talk about the nonprobability sampling it  involves random selection based on conveyance and   other criteria allowing you to easily collect  initial data so the main focus is that it is   flowing you to select samples based on conveyance  probabilities sampling so probability sampling is   based on the fact that every member of population  has known an equal chance of being selected there   are four types of probability sampling the first  is the simple random sampling so this probe simple   random sampling is a technique in which every  member of study population has equal chance   of being selected in the selection of items  completely depends on chance and randomness   and therefore this technique is also known as  method of chance let us assume that we have this   population which represents a broad category  of people of different age sex nationality and   profession and if we have to apply this simple  random technique we will select a sample from   this population based on randomness and my chance  so the sample that we have are from these four   individuals that we have selected so these are  selected based on randomness and by chance the   logic behind using this simple random technique  is to remove the bias on the selection process   next is the systematic sampling in systematic  sampling the first element is selected randomly   from the list or from the sequential files and  then every endeth element is selected let us   assume again that we have this population which  again represent the broad category of people and   if we have to apply this technique of systematic  sampling we will select sample from this on a   based on the fact that we will select first  sample randomly it could be anyone and then   we will apply the innate element from this list so  in this scale we will pick the third element and   remember from the population every third member on  the sequence will picked from the population will   present the systematic sampling this method is  different from simple random sampling since every   possible sample of an earth element is not likely  to be equal clusters sampling so cluster sampling   is a sampling procedure that involves randomly  selecting a particular cluster of an element from   a group of population and subsequently selecting  every element of a selected cluster for study   so with cluster sampling the researchers will  divide the population into separate groups called   clusters which could be groups of externally  homogeneous but internally heterogeneous groups   so then a simple random sample of a cluster  is selected from a population it is assumed   that we have this population which represents  a broad category of people of different age sex   nationality and profession and if we have to apply  this sampling technique they have been divided the   entire population into different groups which is  externally homogenous but internally heterogeneous   group called clusters and after identifying a  particular cluster that we will use for using   this thing we will pick all the elements of that  selected cluster to be included in the study stratified sampling so the probability sampling  procedure that different walls dividing the   entire population into groups or strata defined  by presence of certain critics like your age maybe   based on geography like north south east west or  maybe male or female and then randomly selecting   sample from each strata so let us assume that we  have against this population which represents a   broad category of people and we divide this entire  population into different strata so let us first   divide this into different strata in this case  we are dividing waisting based on mailing female   Adele elderly people and the three status now we  will select a sample from this different three   status based on selecting one person from each  strata at least so this is the stratified sampling   so did you note the difference between the cluster  sampling in the States stratified sampling so with   stratified sampling sample includes a ribbon  from each stratum but with Crystal sampling   samples include element only from one selected  cluster there is a difference between stratified   sampling and the cluster sampling nonprobability  sampling so nonprobability sampling individuals   are selected based on non-random criteria and not  every individual has a chance of being included   in the study this type of sampling is easier  and cheaper to access but you can't use it to   make a valid statistical inference about the whole  population there are few types of nonprobability   sampling first is a convenience sampling it  involves selecting sample based on convenience   a convenience sample simply includes individuals  who happens to be most accessible to the this is   easy and inexpensive way to gather the initial  data but there is no way to tell if the sample   is a true representation of entire population  so it can't produced in a rice result it is   also known as accidental sampling the next type of  nonprobability sampling is the snowball sampling   here you select samples and ask them to refer  them to refer you to others it is also called   known as snowball sampling because in theory  once you have a ball rolling it picks up more   and more snow along the way and becomes large  and larger it is also known as Network sampling so nonprobability sampling we have another  category like quota sampling so quota sampling   means to take very tailored sample that  is in proportion to some characteristic   or traits of a population for example you  divide a publishin by state they live in   income or education level or may be a male or  female this method of sampling is often used   by market researchers where interviewers are  given a quota of subject of a specific type to   attempt to recruit for example an interviewer  might be told to go to and select 20 adult men   20 adult women 10 teenage girls and then 10  teenage boys so that they could interview them   about their television viewing another type of  category is purposive or judgmental sampling it   involves selecting samples based on or his own  judgment this technique relies on judgment of   the researchers who choose the sample based on  his own experience this approach is often used   by media when canvassing the public for opinions  in the qualitative research so that is all I have   on this video see you soon in my next video  now you can follow this still elearning on   all the social media platforms like Instagram  YouTube Twitter and for a regular updates you   can join our Facebook and Lincoln in groups  I will share that link for all these in my   description below thanks for watching distantly  learning I hope you liked this video don't forget   to like and share this video with all your  friends on all the social media platforms