差分

*Missing does not depend on '''unobserved (othermissing) unobserved datavalues'''themselves, but may depend on '''(other) observed datavalues'''*The cause of missing can be explained by

*15% of female participants deny denied to report their body weights after the agreement regardless of measured body weights, but only 1% of male deny denied to report:**Data of female participants are more likely missed not because of data Unobserved (body weightsmissing, unrepoted) themselves but because female are more likely reluctant to report their body weights**In other words, values in the variable ''body weight'' themselves do did not affect the missing , but another variable ''sex'' affects can explain the reason of missing**Missing mechanism is at random, i.e., free from unobserved (missing) values only inside each participant**Missing mechanism is NOT at random, i.e., NOT free from another variable ''sex''; missing of occurred depending on the values in the variable ''body weightsex''