[Systemic]

The survey isn't just "biased" in that 0 isn't an option, it represents a fundamentally different question. The results of this survey can be phrased as: "Out of 76 cars which had their drive units replaced, how many drive units did they have replaced?"

From this poll you can't even say you have a sample size of 76 cars as you only have a sample of 76 cars whose drive units have broken.

A different survey on the same website includes zero [1], and is more appropriate to answering the question of "How likely is it that a Model S will have its drive unit replaced?"

[1] http://www.teslamotorsclub.com/showthread.php/32608-Drive-Un...