Help using Base SAS procedures

Regression analysis

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Super Contributor
Posts: 1,040

Regression analysis

Hi Team,

I have something like shown below,'

                                  Type of Case

                                    CaseA               CaseB        CaseC

Diabetes                        N=                       N=              N=

   Y

   N

AIDS

   Y

   N

Headache

   Y

   N

Fever

   Y

   N

I did a contingency table of :

Diabetes with Cases

Aids with Cases

Headache with Cases

Fever with Cases

Found that the p-values are significant for a couple of them(less than 0.05)

What is the meaning of that statistically?

Also how to do a regression analysis....How do I proceed from there???

Any help is highly appreciated

Regards

Trusted Advisor
Posts: 1,610

Re: Regression analysis

Whenever a p value is less than 0.05, this indicates that the quantity being tested is statistically significant (at the alpha=0.05 level). In layman's terms, this particular arrangement of data that is tested was unlikely to have happened by random chance, it is probably a "real" effect.

You cannot do regression on this data. You need to have continuous X and continuous Y to do a regression.

Super Contributor
Posts: 1,040

Re: Regression analysis

Thanks for the reply.

Could you also provide me with the basics for understanding Logistic Regression ??

Thanks

Trusted Advisor
Posts: 1,610

Re: Regression analysis

Logistic regression is appropriate when you have a continuous X variable, and a categorical Y variable.

For example, if X is temperature, and Y is pass/fail status.

Among other things, logistic regression will compute the probability that you get a pass (or a fail) at a given temperature.

Super User
Posts: 17,758

Re: Regression analysis

You've completed what's known as univariate analysis on your data, checking the category of one variable against others one at a time.

It sounds like you're looking to move on to the multivariate stage, looking at multiple variables together, and relationships between them.

The appropriate multivariate model depends on what your research question/hypothesis is and the structure of your data.

As you've shown all categorical data, my guess is a log-linear model, but that's a GUESS.

Super Contributor
Posts: 1,040

Re: Regression analysis

Hi,

I am trying to study the problems associated with the type of surgery done.

when i use a particular type of surgery what effect/problem it is creating???

Regards

Super User
Posts: 17,758

Re: Regression analysis

So your outcome is an indicator if a patient has a problem?

For me at least I'd need more of an explanation of your data and what you were looking to answer.

Super User
Posts: 17,758

Re: Regression analysis

I'd say consult with a statistician (possibly a biostatistician) now Smiley Happy.There really are too many things that would need to be considered and I've seen too many bad  medical publications to help produce one.

Your local university probably has a consulting services that will be free of charge or low cost.

Super User
Posts: 9,671

Re: Regression analysis

P value less than 0.05 is statistical significant if your possibility of committing the first mistake  is .05 .

That means your H0 hypothesis (Type of Case and Headache are independent ) is not right.

.05 discover there are some correlation between Type of Case and Headache .

I recommend you also use corresponding analysis to check this relation more .

Ksharp

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