The password above contains 52 bits of entropy. This means, it is as random as the result of throwing 52 coins in a row. The reason for that is because every word has been randomly selected from a list of over 8192 distinct words—corresponding to an entropy of 13 bits.
That means, it is as random, as a completely random password of length 8 generated from uppercase letters, lowercase letters and numbers. However it is much more memorable than a complete random password of 8 characters. Or as Randal Munroe puts it:
This is taken from Randall Munroes famous carton .