BookmarkSubscribeRSS Feed
joesocci
Calcite | Level 5

(a) [10] Write a program to draw 100,000 observations from the following bivariate distribution which is uniform over a unit circle. f(x, y) = 1/ℼ where x2 + y2 < 1

(b) [10] Draw the bivariate histogram for x and y. (c) [10] Draw the (marginal) histogram for x .

I've tried transforming x and y so that they vary between (-1,1) and then using the Do while loop so that x2 + y2< 1. Still new to SAS so any would be great.

This is my code so far:


data test; Do i=1 to 10000; Do While x^2 + b^2 <1; x=2*ranuni(111)-1; y=2*ranuni(111)-1; z= x^2 + b^2 <1; end; output; end; run; ods graphics on; proc bivariatete data=test; var x; var y; var z; histogram z; run; ods graphics off;

 

5 REPLIES 5
Reeza
Super User

This is invalid:

x^2

In SAS, the correct operator is **

 

x**2

http://support.sas.com/documentation/cdl/en/lrcon/69852/HTML/default/viewer.htm#p00iah2thp63bmn1lt20...

 

For the histogram, use PROC UNIVARIATE or PROC SGPLOT.

 

PS. You have a lot of other errors in your code. I would suggest doing one step at a time, getting that working and then moving forward. Look at Rick Wicklin blog or book for informaiton on how to simulate data in SAS. If you're a student, since this is clearly homework, your university library may have a digital version available for you to peruse.

joesocci
Calcite | Level 5
Thank you, I've gotten both x and y to vary between (-1,1), I'm still struggling to restrict it so that x^2 + y^2 <1 and output that data. Any suggestions or help would be appreciated!
Ksharp
Super User

It is about data simulation, better post it at IML forum.

what doest f(x,y) looks like,what is its form ?

Rick_SAS
SAS Super FREQ

In addition to the excellent responses from @Reeza and @Ksharp, use PROC KDE to draw the bivariate histogram. The BIVAR statement and PLOTS=HISTOGRAM are what you want to use.

sas-innovate-2024.png

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.

 

Register now!

How to Concatenate Values

Learn how use the CAT functions in SAS to join values from multiple variables into a single value.

Find more tutorials on the SAS Users YouTube channel.

Click image to register for webinarClick image to register for webinar

Classroom Training Available!

Select SAS Training centers are offering in-person courses. View upcoming courses for:

View all other training opportunities.

Discussion stats
  • 5 replies
  • 576 views
  • 4 likes
  • 4 in conversation