# Thread: Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

1. ## Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

Hi All,

I am completing a multiple regression and was hoping to get some advice on whether you believed this scatterplot and Q-Q plot of residuals between the dependent variable and independent variables demonstrates linearity, normality, and homoscedasticity.

To me, I believe the graph seems somewhat linear and homoscedastic, but perhaps non-normal?

It would be great to get your opinions on this and what I could possibly do (using SPSS) to remedy any violations of assumptions.

PS. I have always struggled with statistics, so if you can, please be as simple as possible.

Thank you!!

2. ## Re: Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

So these figures used the model residuals? I could not open attachment, please upload the picture into the thread!

3. ## Re: Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

Yep I believe they are for the model.

Have tried to upload them as jpg's. Let me know if that works!!

4. ## Re: Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

Is the response a count variable?

5. ## Re: Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

The DV is a continuous variable, I believe.

6. ## Re: Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

What is the response?

7. ## Re: Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

I'm unsure what you mean by that (sorry! I said I was bad at stats!)

8. ## Re: Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

What are you trying to predict and how is it measured?

9. ## Re: Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

Can you construct a histogram as well and report the context (y = x + x2 +x3,...,xk; and tell us what the variables are). Is this for a class?

10. ## Re: Determining Linearity, Normality, and Homoscedasticity for Multiple Regression

Apologies for the delay, I have been trying to get my head around everything that I need to know!!

I have attached a histogram of the standardised residuals for the regression model.

This is for my thesis (eek), and what I am looking at is how well 8 IVs predict anxiety score, as well as looking at each individual IV. As it is psychology, the field is not as stringent with regards to assumptions as most statisticians are. However, if you could provide me with your opinion on whether the graphs suggest linearity, homoscedasticity, and normality, I would be so so grateful!!

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