todennäköisyysvälin

todennäköisyysväli is a Finnish term that translates to confidence interval in English. It is a range of values, derived from a sample statistic, that is likely to contain the value of an unknown population parameter. For example, a confidence interval can be used to estimate the mean height of a population based on the average height of a sample of individuals.

The confidence level associated with a confidence interval indicates the probability that the interval contains the true population parameter. Common confidence levels are 90%, 95%, and 99%. A higher confidence level results in a wider interval, meaning there is more certainty that the true parameter lies within the range, but the estimate is less precise. Conversely, a lower confidence level yields a narrower interval, providing a more precise estimate but with less certainty.

The calculation of a confidence interval typically involves the sample statistic, the standard error of the statistic, and a critical value from a probability distribution (such as the normal or t-distribution) determined by the chosen confidence level. The formula generally takes the form of: sample statistic ± (critical value * standard error).

Confidence intervals are a fundamental tool in statistical inference, allowing researchers to quantify the uncertainty associated with estimates derived from sample data. They are widely used in various fields, including scientific research, market analysis, and public opinion polling, to draw conclusions about populations from sample observations.