Q. What is Inference?

Ans.

Inference is the process of deriving conclusions based on facts or premises. We often make inferences based on the results of statistical studies.

For example, suppose a study found that a sample of American teenagers surf the web an average of 4 hours per night. What can we deduce about the population (all American teenagers) from which this sample was taken? Based on this sample, what estimate can we make about the average time all American teenagers surf the web?

First of all, before making any inferences, it is important to analyze the sample population and the sample data carefully. Are there unforeseen correlations between people in the sample? Does every person in your sample of American teenagers own their own computer? If so, then your sample data will be biased because not every household in America has a computer in it.

Let's assume your sample population is a good representation of American teenagers. There are still questions to consider before making inferences. Was the sample data collected during a typical week? Was the Internet atypically slow due to high traffic volume resulting in longer wait times? Were the teenagers from your sample in school or on summer vacation?