Module 1 Statistics 1 Introduction to ANOVA, Regression ...

[WWD]

On page 3-23 within the Course Notes for Module 1, Statistics 1 Introduction to ANOVA, Regression ... the author is analyzing the statistical significance of an interaction term on Sale Price.

The author states that there is a significant statistical difference in Sale Price when looking at Winter vs Spring.

When I look at the immediately preceding table and graph, it looks like the difference is between Spring and Summer.

The t-value for Spring versus Summer is 3.34.  The t-value for Winter versus Spring is -1.89.

What data and results did the author reference when they made their statement about significance on page 3-34?

Bill Donaldson

[Cynthia_sas]

Hi:
We'll ask the course instructors to respond to this question.

Regarding page 3-23, they started with the AMESHOUSING3 data to make the INTERACT data used by the rest of the analysis:

Regarding the data, on page 3-23 it appears that they are using the AMESHOUSING3 data from 3-18 to make the dataset INTERACT, as shown below:

(sorry, I posted the wrong screen shot before)

Thanks, in advance, for your patience,
Cynthia

[Pav]

Hi,

The ANOVA does a pairwise comparison and uses an adjusted P-value (Adj-P Value).

First we compare the SalesPrices of houses with Fair Heating Quality systems.

In the table of comparisons

the adjusted P value for comparing SalesPrice of Fair Heating Qualtiy houses is significantly different between Winter and Summer.

All the other comparisons are not significant for P<0.05

Then they compare the houses with Good Heating Quality:

The conclusion should have said that there was a significant mean sale price difference for houses with good heating systems between the spring months and the Summer months. We will have to adapt that in the course notes. Thank you for pointing that out.

Paul

[WWD · Accepted solution]

Thank you for the quick turn-around!!!

Bill Donaldson