## confidence intervals for mean spring enrollment when fall enrollment is 290

Solved
Occasional Contributor
Posts: 18

# confidence intervals for mean spring enrollment when fall enrollment is 290

I am woring in a data set and have to create a confidence interval for mean spring enrollment when fall enrollment is 290.

I dont understand how to go about doing this especially when the fall enrollment is never 290.

the data is as follows:

data problem2a;

input
Ayear Fall Spring;
if Ayear = 2003 then delete;
datalines;
2001 259 246
2002 301 206
2003 343 288
2004 307 215
2005 286 230
2006 273 247
2007 248 308
2008 292 271
2009 250 285
2010 278 286
2011 303 254
;
run;
proc print data=problem2a;
run;

I understand how to do a basic confidence interval on the enitre thing but not how to specify it.

this is the code I used for a basic CI but I dont think it in doing the right thing.

proc reg data=problem2a;
model spring = fall /clm cli;
run;

Accepted Solutions
Solution
‎01-29-2016 01:47 PM
Super User
Posts: 13,523

## Re: confidence intervals for mean spring enrollment when fall enrollment is 290

Add an additional record for a dummy year (other than one presented) with the value for fall of 290 and a missing spring value.

Look at a regression procedure such as Proc reg and model with spring as the dependent and fall as the independent:

Ask for the predicted values and confidence limits. There will be results in the output to predict and the interval.

I'm not providing exact solution as your dataset name Problem2a looks like homework and you'll learn more looking up the syntax.

Since there doesn't seem to be a requirement for predict if the fall enrollment in 2012 was 309 I would be very tempted to leave Year out of the model.

All Replies
Solution
‎01-29-2016 01:47 PM
Super User
Posts: 13,523

## Re: confidence intervals for mean spring enrollment when fall enrollment is 290

Add an additional record for a dummy year (other than one presented) with the value for fall of 290 and a missing spring value.

Look at a regression procedure such as Proc reg and model with spring as the dependent and fall as the independent:

Ask for the predicted values and confidence limits. There will be results in the output to predict and the interval.

I'm not providing exact solution as your dataset name Problem2a looks like homework and you'll learn more looking up the syntax.

Since there doesn't seem to be a requirement for predict if the fall enrollment in 2012 was 309 I would be very tempted to leave Year out of the model.

Super User
Posts: 23,700

## Re: confidence intervals for mean spring enrollment when fall enrollment is 290

This is known as scoring - you can looking up scoring with respect to PROC REG or PROC SCORE.
🔒 This topic is solved and locked.