Surveys

A survey typically involves a limited number of people who are part of a larger population, and by chance alone there will almost always be some differences between a sample and the population from which it was drawn. These differences are known as “sampling error” and they are expected to occur regardless of how scientifically the sample has been selected. The advantage of a scientific sample is that we are able to calculate the sampling error. Sampling error is determined by four factors: the population size, the sample size, a confidence level, and the dispersion of responses.

Because the sample of 400 respondents was drawn from the estimated population of approximately 57,421 adult residents in the City of Chico, one can be 95 percent confident that the margin of error due to sampling will not vary, plus or minus, by more than 4.9 percent for the survey. For a question with two response options (e.g., Yes/No), we can be 95 percent confident that the difference between the percent breakdowns of the sample and those of the total population is no greater than 4.9 percent. The percent margin of error applies to both sides of the answer – for a question in which 50 percent of respondents said yes, one can be 95 percent confident that the actual percent of the population that would say yes is between 45 percent and 55 percent.

In addition to a margin of error below 5 percent, the survey also collected a sample of respondents that is representative of adult residents in the City of Chico in terms of gender, age, and ethnicity. In other words, the residents who participated in the study reflect the current Census estimates for the City.

For additional information please contact Kendall Flint at info@chicogeneralplan.com.