Q. Example of Selection a Sample?
Ans.
Suppose a presidential election is approaching and many people are interested in knowing which candidate is most likely to win the vote. You have been assigned the task of predicting the future president one month before Election Day. How do you do it?
Solution: Here is one way that you might approach this problem. Use the 4 steps listed above.
1) The objective of this survey is to determine what percent of voters are likely to vote for the republican candidate, the democratic candidate or another candidate.
2) The variable is the way each member of the population chooses to vote. The population is all of the registered American voters.
3) You may decide to randomly dial phone numbers using U.S. area codes until you find 1000 registered voters. Ask them which candidate they plan to vote for.
4) If the sample you have chosen is a good representation of the voting American public, then you might assume that the percentage of voters in your sample who chose to vote republican will be the same percentage of voters in the entire population who will vote republican. You can assume the same for the democratic candidate as well as the other candidates.