A probability distribution tells you the probability of something happening,the probability of the random variabletaking the valueA Cumulative distribution tells you the probability of the random variabletaking a value less than or equal to a valueoften written
Given a probability distributionwe can find the cumulative distribution:
Ifis presented in a table, add the entries as you go along.
Ifis presented as a function, integrate. Supposethen
Given a cumulative distributionwe can find the probability distribution:
Ifis presented in a table, subtract successive entries as you go along.
Ifis presented as a function, differentiate. Supposethen