Browse Groups

• ## Statistical Learning Example Section 20.1

(1)
• NextPrevious
• Has anyone tried to work the example on pages 713/714 (second edition)? I cannot got equation 20.1 to match the graph on page 714 (figure 20.1(a)). For
Message 1 of 1 , Dec 3 9:22 AM
View Source
Has anyone tried to work the example on pages 713/714 (second
edition)? I cannot got equation 20.1 to match the graph on page 714
(figure 20.1(a)).

For example, consider P(h5|d) = alpha * P(d|h5)P(h5). In this case P
(d = lime|h5) is always 1. For the ten trials,

P(d1 ...d10|h5) = 1**10 = 1. (20.3)
P(hi) = .1

So P(h5|d) = (.1 * alpha) from equation 20.1. Assume alpha = 1/P(d =
lime) = 1/.5 = 2. So after one candy is unwrapped, P(h5|d) = .2 as
shown in figure 20.1(a).

On the next trial (i.e. second candy is also lime) P(d|h5) = 1 (as
above from eqn 20.3). Then P(h5|d) = (1) * (.1) * alpha. The value on
figure 20.1 is shown as approximately .3 - implying alpha = 3
Subsequent calculations for alpha appear to 4, 5 etc.

I can't seem to see how alpha is calculated ..... Any opinions are
greatly appreciated.

Paul Comitz
Your message has been successfully submitted and would be delivered to recipients shortly.
• Changes have not been saved
Press OK to abandon changes or Cancel to continue editing
• Your browser is not supported
Kindly note that Groups does not support 7.0 or earlier versions of Internet Explorer. We recommend upgrading to the latest Internet Explorer, Google Chrome, or Firefox. If you are using IE 9 or later, make sure you turn off Compatibility View.