<Tr> <Td> Poisson </Td> <Td> Transactions Per Paying User </Td> <Td> E-test </Td> <Td> C - test </Td> </Tr> <Tr> <Td> Multinomial </Td> <Td> Number of each product Purchased </Td> <Td> Chi - squared test </Td> <Td> </Td> </Tr> <Tr> <Td> Unknown </Td> <Td>--</Td> <Td> Mann--Whitney U test </Td> <Td> Gibbs sampling </Td> </Tr> <P> Like most fields, setting a date for the advent of a new method is difficult because of the continuous evolution of a topic . Where the difference could be defined is when the switch was made from using any assumed information from the populations to a test performed on the samples alone . This work was done in 1908 by William Sealy Gosset when he altered the Z - test to create Student's t - test . </P>

A change in revenue between two alternatives is known as