The central limit theorem (ˌsɛntrəl ˈlɪmɪt ˈθiərəm) is a statistical concept that explains how the average results of a large number of random samples from a given population will approximate a normal distribution. The spelling of this phrase follows the rules of English orthography and pronunciation, with the stress falling on the second syllable of "central" and the first syllable of "limit." The use of IPA phonetic transcription helps explain the particular sounds and stress patterns that make up this important term in statistics.
The central limit theorem (CLT) is a fundamental concept in probability theory and statistics that states that when independent random variables are added, the sum or average of those variables converges to a normal distribution (also known as a Gaussian distribution), regardless of the shape of the original distribution.
More precisely, the central limit theorem suggests that if a large enough sample size is taken from any population, the distribution of the sample means will tend to be approximately normally distributed, regardless of the actual distribution of the population. This means that even if the original distribution of the data is skewed or has outliers, when a large enough sample is taken, the sample means will become more symmetric and bell-shaped.
The central limit theorem plays a crucial role in statistical inference and hypothesis testing. It allows statisticians to make generalizations and draw conclusions about a population based on a sample. Furthermore, it provides a theoretical foundation for many statistical techniques such as confidence intervals and hypothesis tests.
In practice, the central limit theorem is widely applied across various fields, such as economics, biology, social sciences, and engineering, as it provides a reliable framework for analyzing and interpreting data. By understanding the central limit theorem, statisticians and researchers can make more accurate predictions and inferences about populations based on samples, thereby ensuring the validity of their statistical analyses.