# Thread: Multiple Linear Regression - really need help

1. ## Multiple Linear Regression - really need help

Hi, I'm going out of my mind...really need help.

I have one continuous dependent variable (test scores) and 6 categorical (with 2 categories - e.g. male/female) independent variables.

I want to look at the association/relationship between them or does the independent variables have an effect on the dependent.

What test can I use? I have tried Multiple Linear Regression but the data doesn't pass any of the asssumptions.

2. ## Re: Multiple Linear Regression - really need help

What test can I use? I have tried Multiple Linear Regression but the data doesn't pass any of the asssumptions.
What do you mean by this?
And how large is your sample size?

With kind regards

K.

3. ## The Following User Says Thank You to Karabiner For This Useful Post:

101lou (04-02-2014)

4. ## Re: Multiple Linear Regression - really need help

There are 68 participants.
I have tried multiple linear regression, i read their are 8 assumptions the data has to pass before you can run the test? linearity, normal distribution etc except their isn't a linear relationship between my dependent and independent variables or they are not normally distributed

5. ## Re: Multiple Linear Regression - really need help

initially i want to use chi square but the dependent variable would have to be categorical and mine is continuous (can't be categorised)

7. ## Re: Multiple Linear Regression - really need help

their isn't a linear relationship between my dependent and independent variables
You said you had 6 binary variables, so the bivariate
relationships cannot be non-linear.
or they are not normally distributed
I am not sure what you mean by this. You have
to check the residuals of the multiple regression;
the residuals should be from a normal population
(but with n > 50 departures from this are not
cosidered serious).

With kind regards

K.

8. ## The Following User Says Thank You to Karabiner For This Useful Post:

101lou (04-03-2014)

9. ## Re: Multiple Linear Regression - really need help

OK thanks! So I am doing the right test by doing Multiple Linear Regression?

10. ## Re: Multiple Linear Regression - really need help

I assume you used dummy independent variables. Ordinal independent dvariables are I believe always linear and I assume this includes dummies. Why do you conclude they are not linear?

11. ## Re: Multiple Linear Regression - really need help

Noetsi can you clarify your last answer, I have run into this problem as well. I was always told that the relationship between the Dependent variable and the independent variable had to be linear... If you have a dummy variable (say male =1 female=0) then by definition you are comparing groups and the variable are not linearly correlated). it is therefore assumed that since dummy variables basically split the data into groups, they are linerally related to the dependent variable?

On a related question, does the Independent variable have to be normally distributed related to the dependent variable? meaning if one variable was age and another was income, what if income was FAR more variable at young ages than it is at old ages (it is). SO what is you have heteroscetastic data in a scatter plot of Age vs Income? Does that matter, or is it only the normal assumption of the residuals that matter?

Thanks so much!

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