Write a program similar to Problem 4.5, except that we want to include all the data for each patient, excluding any patient who has had only one visit. Instead of having PROC MEANS create printed...

Write a program similar to Problem 4.5, except that we want to include all the data for each patient, excluding any patient who has had only one visit. Instead of having PROC MEANS create printed output, use it to create a SAS data set (PAT_MEAN) containing the mean for each patient (use the AUTO NAME output option to name these variables).