文档介绍：16 Resampling: The New Statistics
AFTERNOTE 1
TO Dramatizing the
INTRODUCTION Power of Simulation
A problem in probability is at the heart of every problem in
statistics. Problems in probability often can be very confusing
to the intuition. And formulas often either do not aid the intu-
ition, or lead to the wrong answer, or both. But simulation can
often get you the right answer and also help you understand
why it is correct. Let’s dramatize the point with puzzles:
1. If a family has two children and one of them is a boy, what
is the probability that the other will also be a boy?
Most people—even professional statisticians—often quickly
answer “one half.” That is not correct.
The solution is not obvious even after the person has decided
to tackle the problem by simulation. It is not unusual for a per-
son to say: I flip one coin, and if it is a head (boy), I then flip
another coin and see how often that will be a boy, also, and
then actually flip the coin once and record the es. But
that experiment does not resemble the situation of interest. A
proper modeling throws two coins, examines to see if there is
a head on either, and then examines the other.
Or consider a two-digit column of random numbers in Table
i-A1-1, using odd numbers for females and even numbers for
males. The first fifty lines are sufficient to suggest the corre