You have a poor understanding of sentience. If an AI ever were to achieve sentience, it would be fully capable of reasoning and thinking like a human. Humans can and do change their motivations based on their experiences, a fully sentient AI would be no different.
That being said, I believe we’re centuries away from creating sentience, if it’s even possible, so I’m not too worried about “I, Robot” coming true any time soon.
I agree with what you’re saying for the most part, but for a population the size of Australia with 1000 respondents, a 99% confidence level has a margin of error of 4% which is perfectly acceptable. Unless the survey targeted very specific demographics versus a random sample, it should be very accurate.