Formulas are given for the expectation and variance of the number of components for two definitions of random graphs. The results extend those of R. F. Ling (1973).
"The Expectation and Variance of the Number of Components in Random Linear Graphs." Ann. Probab. 3 (1) 159 - 161, February, 1975. https://doi.org/10.1214/aop/1176996455