How to Make Inferences From Lots of Data

If you wanted to figure out how many people woted for a trump or for brekset ia particular city, normally you would just call up a few thousand people and ask them directly. But then you have a phone number and an answer. So that's very dangerous. If you do it in a differentially private way, you call them and you ask them to flip a coin. And if it lands on heads, they tell you the truth. If it lands on tails, they tellou the truth. The person never tells you what the coin, how the coin lands. They just give you an answer. That means that 75% of your answers are true, 25 % of