Lesson 5: Regression Models Using SAS Enterprise Miner quiz question nr. 3

[_KoAn_]

Hi,

I have a question regarding Lesson 5 Regression Models Using SAS Enterprise Miner quiz question nr. 3 (see below). If I understand correctly, if you choose 'none' then non significant variables are not removed? So why is the correct answer d?

Best regards,
Koen

Which of the following sequential selection methods do you use so that SAS Enterprise Miner will look at all variables already included in the model and delete any variable that is not significant at the specified level?

a.  Backward b.  Forward c.  Stepwise d.  None

Your answer: a Correct answer: d

The stepwise selection method compares each variable to the previous variable entered and based on a specified level, one variable is considered more significant than the other.

[Cynthia_sas]

Hi:
  Thanks for asking pointing this out, our e-learning developers and course instructors are clarifying and correcting this question. Based on the question, the correct answer should be A: Backward. D is not a sequential selection method, nor does it remove any variables from the model.
 
  One of the instructors for the course has refined the explanation for why Backward is the correct answer. Here's the explanation:
 
'In the Enterprise Miner Regression node, the "selection model" property lists 4 possible choices.  If Backward is selected, training begins with all candidate effects in the model and removes effects until the Stay significance level or the stop criterion is met. If Forward is selected, training begins with no candidate effects in the model and adds effects until the Entry significance level or the stop criterion is met. If Stepwise is selected, training begins as in the Forward model but may remove effects already in the model. This continues until the Stay significance level or the stop criterion is met. If None is selected, all inputs are used to fit the model.'
 
  Thanks again, for reporting this. We'll update the quiz in the course.
 
Cynthia

[_KoAn_]

Hi Cynthia,

Thank you for your explanation and I'm glad to know that answer A: Backward is correct.

Best regards,

Koen