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.
Join us for SAS Innovate April 16-19 at the Aria in Las Vegas. Bring the team and save big with our group pricing for a limited time only.
Pre-conference courses and tutorials are filling up fast and are always a sellout. Register today to reserve your seat.
ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.
Find more tutorials on the SAS Users YouTube channel.