Is a larger sample always better than a smaller sample?
Larger samples are generally more precise, but sometimes not. The important rule in sampling is not how many poll respondents are selected but, instead, how they are selected. A reliable sample selects poll respondents randomly or in a manner which insures that everyone in the area being surveyed has a known chance of being selected. Top 3. How can a sample of only 800 or 1200 truly reflect the opinions of 200 million Americans within a few percentage points? Sampling methods and measures of sample reliability or precision are derived from a mathematical science called statistics. Statistics is a subject taught in colleges and some high schools. Text books on the subject are available in most libraries. At the root of statistical reliability is probability; i.e., the odds of obtaining a particular outcome by chance alone. As an example, the chances of having a coin come up heads in a single toss is 50%. Heads is one of only two possible outcomes. The chance of getting two heads in two
