Hello,
I am a beginner stat student. I am trying to plot observed and predicted Poisson and negative binomial probabilities against the
data observed. I have no experience or prior knowledge of graphing. I am getting lost in all complex explanations.
Can you please help me in simplest way of accomplishing this task?
Below is my syntax. How do I plot predicted Poisson and negative binomial probabilities against the sample below?
data world;
input scores @@;
datalines;
5 1 6 3 2 1 2 1 1 2 1 3 3 3 3
4 1 1 1 2 1 3 2 2 3 7 3 3 7
4 3 3 3 2 4 2 0 3 3 3 2 4 2
1 1 1 3 7 3 2 2 2 5
;
proc means data=world n mean var;
run;
/* Mean= 2.67 and Variance=2.56. The data is a good canfidate for poisson distribution. */
proc genmod data=world;
model scores= /dist=poisson link=log;
run;
Another example that produces both an observed vs. expected plot (using PROC COUNTREG) and a test of the fit (using PROC FREQ) is shown in this note.
Follow the example in the article "Fitting a Poisson distribution to data in SAS."
The only difference is that your response is named 'scores' instead of 'N' and your counts are 0-7 instead of 0-13.
Can you please share the link again? It is not working.
Another example that produces both an observed vs. expected plot (using PROC COUNTREG) and a test of the fit (using PROC FREQ) is shown in this note.
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