Tillitsintervall

A confidence interval, or tillitsintervall in Norwegian, is a range of values that is likely to contain the true value of a population parameter. It is calculated from sample data and is used to estimate an unknown population characteristic, such as the population mean or proportion. The confidence level, often expressed as a percentage, indicates the probability that the interval contains the true parameter if the same sampling procedure were repeated many times. Common confidence levels are 90%, 95%, and 99%.

The width of a confidence interval is influenced by two main factors: the variability of the data and the desired confidence level. Higher variability in the sample leads to a wider interval, as it indicates greater uncertainty. Conversely, a higher confidence level also results in a wider interval because it requires a broader range to be more certain of capturing the true parameter. A narrower confidence interval provides a more precise estimate, while a wider interval offers greater confidence in containing the true value.

Confidence intervals are essential tools in statistical inference, allowing researchers and analysts to quantify the uncertainty associated with their estimates derived from sample data. They are widely used in various fields, including scientific research, market analysis, and opinion polling, to draw conclusions about populations based on limited observations.