10×12 DataFrame
 Row │ Subject  Period  Trt       Base   Age    seizures  trt_active  base_log  age_log  period_f  period_centered  trt_period_centered
     │ Int64    Int64   String15  Int64  Int64  Int64     Float64     Float64   Float64  Float64   Float64          Float64
─────┼──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
   1 │       1       1  placebo      11     31         5         0.0   2.48491  3.46574       1.0              0.0                  0.0
   2 │       1       2  placebo      11     31         3         0.0   2.48491  3.46574       2.0              1.0                  0.0
   3 │       1       3  placebo      11     31         3         0.0   2.48491  3.46574       3.0              2.0                  0.0
   4 │       1       4  placebo      11     31         3         0.0   2.48491  3.46574       4.0              3.0                  0.0
   5 │       2       1  placebo      11     30         3         0.0   2.48491  3.43399       1.0              0.0                  0.0
   6 │       2       2  placebo      11     30         5         0.0   2.48491  3.43399       2.0              1.0                  0.0
   7 │       2       3  placebo      11     30         3         0.0   2.48491  3.43399       3.0              2.0                  0.0
   8 │       2       4  placebo      11     30         3         0.0   2.48491  3.43399       4.0              3.0                  0.0
   9 │       3       1  placebo       6     25         2         0.0   1.94591  3.2581        1.0              0.0                  0.0
  10 │       3       2  placebo       6     25         4         0.0   1.94591  3.2581        2.0              1.0                  0.0