Well, use of those would make the mean meaningless.
It wouldn’t be a problem if the polls had upper and lower bounds, because then you could exclude them (but you could also make the upper bound infinite if you wanted to). I don’t think there’s a need for them, though.
You don’t need to use infinities to make the mean meaningless: giving answers such as 1e100 will suffice. On the other hand, NANs are traditionally just disregarded when computing means (i.e., the mean of 1, 2, 3 and NAN is taken to be 2) -- essentially they would amount to a blank vote.
Well, use of those would make the mean meaningless.
It wouldn’t be a problem if the polls had upper and lower bounds, because then you could exclude them (but you could also make the upper bound infinite if you wanted to). I don’t think there’s a need for them, though.
You don’t need to use infinities to make the mean meaningless: giving answers such as 1e100 will suffice. On the other hand, NANs are traditionally just disregarded when computing means (i.e., the mean of 1, 2, 3 and NAN is taken to be 2) -- essentially they would amount to a blank vote.