Question: Why Statistics ?
Answer: Statistics is used for decision making often to bring certainty to the decision.

Question: Why do inferential statistics ?
Answer : Let’s say  I want to find the no of brown ducks in the population i.e Fig 1.

Fig 1: Find no of grey ducks here

Question : Oh.. this is tough. It’s time consuming and takes a lot of tiducks in small areame and hence expensive? How do we make it easier ?
Answer: What if  we make the task easier by only counting over a small area. Umm.. nice idea.. Let’s do that…

 

Question : Yes this is easier to count here.  Cool…  But what is the con ?
Answer : Yes, it definitely is easier  but the con is we slightly loose accuracy here  because we only are taking a sample here. This exactly is the inferential statistics. The process of making inference about the population based on the small sample size which we use just because the small sample size makes the whole process feasible. 

Since performing a test on the whole population is very very expensive and infeasible, we use   inferential statistics to perform the test.

Question : So how do you do the inferential statistics ?
Answer : We perform the test on the sample of the population. this  is less expensive and feasible.

Question: Awesome, Is there any problem to this approach?
Answer : Actually, there is. There is a lot of problem with this approach and we have to be very careful in numerous areas i.e
1. Sample population different than actual population e.g Including college students only  to infer the results for the whole population
2. Sample size  too small.

Question : What are the consequences of  using samples  ?
Answer: In inferential statistics since, we  use the information for the sample to infer the conclusion about the population, it means that there is no guarantee but only the probability of being correct.

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