## Asignment 1 Problem 2

Moderator: Statistisches Maschinelles Lernen

X-Out
Windoof-User
Beiträge: 28
Registriert: 14. Mai 2007 19:06

### Asignment 1 Problem 2

Hi,

I'm confused because of this exercise. Are we supposed to answer question "Part A" and B or the questions below starting with "(10 points)"?

The problem is in Part A your asking about an univariat distribution and a statement about a condition for the decision boundary is asked. But below this task is about the bivariat distribution and here we are only looking for the shape of the boundary but no conditions.

sroth
Dozentin/Dozent
Beiträge: 37
Registriert: 20. Sep 2007 15:00

### Re: Asignment 1 Problem 2

You have to do both parts:

The questions in the bullet points (with 10 points each) belong to part B, i.e. the bivariate case.
Part A on the other hand (20 points) is about univariate Gaussians; only the tasks described in the 6 lines of text starting at "Part A" are relevant for this problem.

Hope that clarifies it,
Stefan Roth

xAx
Endlosschleifenbastler
Beiträge: 157
Registriert: 6. Mär 2008 17:20

### Re: Asignment 1 Problem 2

Part B, Task 1 asks me to "plot these distributions". Which ones exactly? For example: either p(x | C_1) or p(x | C_1) * p(C_1)?
Nichts ist wie es scheint!
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Zuletzt geändert von xAx am 14. Mär 2009 16:17, insgesamt 99-mal geändert.

sroth
Dozentin/Dozent
Beiträge: 37
Registriert: 20. Sep 2007 15:00

### Re: Asignment 1 Problem 2

You have two options (both are fine):
* If you plot them into separate coordinate systems (e.g. with subplot), then either p(x|C_1) or p(x | C_1) p(C_1) is fine, since the prior just rescales the function.
* If you plot both into the same coordinate system (i.e. with "hold"), you should use the joint, e.g. p(x | C_1) p(C_1).

Stefan Roth