Abstract: The paper dealt with Type I censored sample by EM algorithm. Observed failure data were used to estimate unobserved failure data, and the distribution's estimated parameter was obtained. Moreover, a comparison of EM algorithm, maximum likehood estimation and a modified maximum likehood estimation was made. Finally,EM algorithm was used to statistical analysis for zero-failure data, and to estimate the exponential distribution's parameter.

Key words: exponential distribution, zero-failure data, time curtailed test, EM algorithm, maximum likelihood estimation, revised maximum, likelihood estimation  ,