luottamusvälisten

Luottamusvälinen is a Finnish term that translates to "confidence interval." In statistics, a confidence interval is a range of values, derived from sample statistics, that is likely to contain the value of an unknown population parameter. It is a measure of the uncertainty associated with a statistical estimate.

When conducting statistical analysis, researchers often use a sample from a larger population to make inferences about that population. For example, a pollster might survey a sample of voters to estimate the proportion of the entire electorate that supports a particular candidate. The sample proportion will likely not be exactly equal to the true population proportion. A confidence interval provides a range within which the true population proportion is estimated to lie, with a certain level of confidence.

The confidence level, typically expressed as a percentage (e.g., 90%, 95%, 99%), indicates the probability that the confidence interval will contain the true population parameter if the sampling process were repeated many times. A higher confidence level results in a wider interval, reflecting greater certainty but less precision. Conversely, a lower confidence level yields a narrower interval, offering more precision but with less certainty.

The width of a confidence interval is influenced by several factors, including the sample size, the variability of the data, and the chosen confidence level. Larger sample sizes generally lead to narrower confidence intervals, as they provide more information about the population. The margin of error is a key component of a confidence interval, representing the "plus or minus" value added to the sample statistic to define the upper and lower bounds of the interval.