Question

• Ever wonder why a survey of the American population often has what seems like a very small sample size? 2000 people can tell us what the American population is thinking about. We have formulas to calculate an appropriate sample size for both estimation of the mean and estimation of the proportion. How do they work and why do we need so few to tell us what so many might be thinking?

Answer 1

Yes, a survey of the American population often has what seems like a very small sample size.

Answer:- It is because of the power of Statistics, in specific because of the strength of Sampling techniques.

Due to having a large population, Considering whole population is very uneconomical in terms of time as well as money.

And it is found that Sampling techniques if effectively and effeciently used can give us nearly the same information as given by the entire population by using just a part of it, often called as Sample.

Also, the margin of error plays a very significant role here.

The margin of error is related inversely with the square root of the sample size,n. So more the sample size lesser will be the margin of error.But increasing sample size beyond a certain limit results in considerable increase in time as well as money to conduct the experiment on a large sample.

So, taking a small sample, we ensure that the sample is randomly chosen, is a good representative of the population, where good means the sample reflects the properties of the population and also we make sure that the sample is within the margin of error.

Hence, they work in this way using the effecient sampling techniques to come up with valuable and precise results.

Above mentioned are the reasons they need to work with so few to tell us what so many might be thinking.

The same approach of sampling is used in surveys not just in America but all over the world.

Remember, sampling techniques are good and bring us good results only if applied correctly and the sample is a good representative of the population.

You must also know about some of the well known examples in History , where sampling techniques have failed due to wrong implementation.

As you have asked about America, I kindly request you to search on internet "Dewey Defeats Truman" and read in detail what actually went wrong in the sampling method chosen by the famous newspaper company which caused them a huge embarrassment and disgrace in the 1948 U.S. Presidential Election. Please read it.You will definitely learn something useful from it.