Follow @ProbabilityPuz          Q: You are conducting a survey and want to ask an embarrassing yes/no  question to subjects. The subjects wouldn't answer that embarrassing  question honestly unless they are guaranteed complete anonymity. How  would you conduct the survey?   Machine Learning: The Art and Science of Algorithms that Make Sense of Data   A: One way to do this is  to assign a fair coin to the subject and ask them to toss it in private.  If it came out heads then answer the question truthfully else toss the  coin a second time and record the result (heads = yes, tails = no). With  some simple algebra you can estimate the proportion of users who have  answered the question with a yes.   Assume total population  surveyed is \(X\). Let \(Y\) subjects have answered with a "yes". Let  \(p\) be the sort after proportion. The tree diagram below shows the  user flow.     The total expected number of "yes" responses can be estimated as  $$  \frac{pX}{2} +...