Jerzy Neyman (April 16, 1894 – August 5, 1981), born Jerzy Spława-Neyman, was a Polish mathematician and statistician who spent the first part of his professional career in various institutions in Warsaw, Poland, and the second part at the University of California, Berkeley. Neyman first introduced the modern concept of a confidence interval into statistical hypothesis testing and co-devised null hypothesis testing (in collaboration with Egon Pearson).

He was born into a Polish family in Bendery, Bessarabia in Imperial Russia, the fourth of four children of Czesław Spława-Neyman and Kazimiera Lutosławska. His family was Roman Catholic and Neyman served as an altar boy during his early childhood. Later, Neyman would become an agnostic. Neyman's family descended from a long line of Polish nobles and military heroes. He graduated from the Kamieniec Podolski gubernial gymnasium for boys in 1909 under the name Yuri Cheslavovich Neyman. He began studies at Kharkov University in 1912, where he was taught by Russian probabilist Sergei Natanovich Bernstein. After he read 'Lessons on the integration and the research of the primitive functions' by Henri Lebesgue, he was fascinated with measure and integration.

In 1921 he returned to Poland in a program of repatriation of POWs after the Polish-Soviet War. He earned his Doctor of Philosophy degree at University of Warsaw in 1924 for a dissertation titled "On the Applications of the Theory of Probability to Agricultural Experiments". He was examined by Wacław Sierpiński and Stefan Mazurkiewicz, among others. He spent a couple of years in London and Paris on a fellowship to study statistics with Karl Pearson and Émile Borel. After his return to Poland he established the Biometric Laboratory at the Nencki Institute of Experimental Biology in Warsaw.

He published many books dealing with experiments and statistics, and devised the way which the FDA tests medicines today.

Neyman proposed and studied randomized experiments in 1923. Furthermore, his paper "On the Two Different Aspects of the Representative Method: The Method of Stratified Sampling and the Method of Purposive Selection", given at the Royal Statistical Society on 19 June 1934, was the groundbreaking event leading to modern scientific sampling. He introduced the confidence interval in his paper in 1937. Another noted contribution is the Neyman-Pearson lemma, the basis of hypothesis testing.

In 1938 he moved to Berkeley, where he worked for the rest of his life. Thirty-nine students received their Ph.D's under his advisorship. In 1966 he was awarded the Guy Medal of the Royal Statistical Society and three years later the U.S.'s National Medal of Science. He died in Oakland, California in 1981.