I had fun announcing my pregnancy. At six weeks, I decided to tell my immediate family. I sent each of them a personalized email (e.g. for my brother who likes Scrabble I sent him a picture of tiles which when unscrambled read "Uncle S_____"). On their own, some of them may have been a bit too vague, but I think all together they worked.
Only problem was, my dad was on a business trip at the time so he didn't get to see all the pieces come together. Here is our email exchange:
His response:Hi Dad,
I've got a probability problem for you that I would like your help with.
"Suppose a generic test is able to detect the chemical hCG with 99% accuracy. Suppose false positives occur 0.01% of the time. If a certain woman performs the test and it comes back positive, what is the probability that she actually does contain the chemical hCG?"
I don't think this problem has enough information (I can't fill in all the spots for normal Bayes rule stuff). What do you think?
And then he kept ignoring his phone all day even though my mom and I called him a few times. So that announcement sort of failed.H0 = HCG absent
H1 = HCG present
P(detect HCG|present) = .99
P(detect HCG|absent) = 0.0001
P(present|detect HCG) = P(detect HCG | present) P(present)/(P(detect HCG|present) P(present) + P(detect HCG|absent)P(present))
So, it appears that you need a prior probability P(present) = 1 - P(absent).
What fun announcements have you seen?