https://communities.sas.com/t5/Statistical-Procedures/Surveymeans-and-confidence-limits/m-p/62821#M2961 SURVEYMEANS does take df into account. The df calculation depends on whether you have clusters and/or strata. In the simplest case, with no clusters or strata (which means that each observation is a cluster), df = number of observations - 1. For your example, 2.04 IS the critical t value (with alpha=.05). By the way, CI is SE*t (not SD*t).<BR /> <BR /> You can see the calculated df value by putting df in the procedure statement. Mon, 09 May 2011 12:55:37 GMT lvm 2011-05-09T12:55:37Z https://communities.sas.com/t5/Statistical-Procedures/Surveymeans-and-confidence-limits/m-p/62820#M2960 I have a question about the estimation about confidence limits and proc surveymeans.<BR /> <BR /> When we estimates the confidence limits, it seams that SAS does not take the df in account? It makes just a point estimate with SD * 2.04.<BR /> <BR /> Is this the correct behavior? or is there a way to make SAS adjust the 2.04 coefficint according to the df and the numbers in the t-tables? Fri, 06 May 2011 08:52:10 GMT https://communities.sas.com/t5/Statistical-Procedures/Surveymeans-and-confidence-limits/m-p/62820#M2960 AndersBergquist 2011-05-06T08:52:10Z https://communities.sas.com/t5/Statistical-Procedures/Surveymeans-and-confidence-limits/m-p/62821#M2961 SURVEYMEANS does take df into account. The df calculation depends on whether you have clusters and/or strata. In the simplest case, with no clusters or strata (which means that each observation is a cluster), df = number of observations - 1. For your example, 2.04 IS the critical t value (with alpha=.05). By the way, CI is SE*t (not SD*t).<BR /> <BR /> You can see the calculated df value by putting df in the procedure statement. Mon, 09 May 2011 12:55:37 GMT https://communities.sas.com/t5/Statistical-Procedures/Surveymeans-and-confidence-limits/m-p/62821#M2961 lvm 2011-05-09T12:55:37Z