Hi guys, I have a very basic question, but could not find the convincing answer from Interest. I have two groups with different number of observations.  I have already got the mean and median of the two group and the figure shows group A is larger than group B. But I do not know whether these are significant or not. So I want to do the univariate test to look at whether they have the same mean and same median. According to papers, the basic steps is to do t-test for mean and Wilcoxon test for median. But I have several questions regarding this: 1. Shall I use the one-sided t-test or two-sided t-test? What I did is using the coed below: Proc ttest data=;   class ;   var ; run; Will this give me the one-sided t-test or two-sided t-test? And what is the common practice in the paper when they show whether the two group has different mean? one-sided or two-sided? 2. About the Wilcoxon test to test whether they have same median, shall I use Wilcoxon rank-sum test or Wilcoxon signed-rank test? I did see both but I do not know which to use. And also when I read the result from SAS, shall I use the one-sided result or two-sided? I used the following code: proc npar1way data = wilcoxon;   class;   var ; run; I really do not know which is the right way. I really appreciate your help. Cheers. ... View more

Hi all, I am having a question about how to run the regression if the dependent variable is a ranking number? For example, I want to look at what kind of factors will determine a person's education level. So my dependent variable: EDUCATION= 1: PhD                       2: Master                       3: Undergraduate                       4: High School                       5: less than high school. My independent variables are some continuous variables or dummy variables let's say: the person's IQ, his parent's salary... I know that if the dependent is a dummy variable which has only 1 or 0, I can use Logit/Probit model. And if the dependent variable is categorical and cannot be ordered in any meaningful way, then I could use multinomial logistic regression. But here the dependent variable has more than 2 categories and it is a rank which mean less value is better (for example, 1 is better than 5). So how could I run this regression? Thanks a lot for you help. ... View more

Hi all, My observations have FOUR variables: ID, DATE, year1 and year2. I want to create times series(frequency: yearly) data between year1 and year2. I have already use proc transpose to create a variable YEAR which has year1 and year2 for each observation. for example for observation A, if year1=1995 and year2=2006, then after the proc transpose I will have two observations A1 with YEAR=1995 and A2 with YEAR=2006. Then I want to create all the time series observations with YEAR between 1995 and 2006. Namely, Year=1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005. I tried to use proc expand to solve the problem(I did so with monthly data), but the code below does not work:# proc expand data=mysample out=mysample1 From=year to=year; by ID Date; id YEAR; convert YEAR; run; The code does not work. Is it because I should not use Proc expand or is there something wrong with the code? Or could anyone tell how to solve the problem? Many thanks! ... View more

Hi all, My observations have FOUR variables: ID, DATE, year1 and year2. I want to create times series(frequency: yearly) data between year1 and year2. I have already use proc transpose to create a variable YEAR which has year1 and year2 for each observation. for example for observation A, if year1=1995 and year2=2006, then after the proc transpose I will have two observations A1 with YEAR=1995 and A2 with YEAR=2006. Then I want to create all the time series observations with YEAR between 1995 and 2006. Namely, Year=1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005. I tried to use proc expand to solve the problem(I did so with monthly data), but the code below does not work:# proc expand data=mysample out=mysample1 From=year to=year; by ID Date; id YEAR; convert YEAR; run; The code does not work. Is it because I should not use Proc expand or is there something wrong with the code? Or could anyone tell how to solve the problem? Many thanks! ... View more