I was recently asked the following question in an interview.
I had to identify what is the size of the market which is interested in buying Organic Milk in the City. I was given a survey and had to find out a sample to get the results.
I came up with the profile of people who should be targeted for the survey (People who live in costly localities, have their own house, etc.). Based on the profile I estimated that somewhere around 600,000 lived in the city.
Then I was asked the following questions 1. What should be the number of people who should be surveyed? 2. How can I confirm whether the sample I just surveyed is a representative of the population? 3. What would be the level of significance of the same? And Why?
Can anyone help me out here, please?