Drugstore1 Dataset                      1

    Obs    product           chain        store_id    price

      1    antacid           CVS             101       9.37
      2    antacid           CVS             102      11.78
      3    antacid           CVS             103      10.05
      4    antacid           CVS             104      12.13
      5    antacid           CVS             105      11.14
      6    antacid           Osco            202       8.23
      7    antacid           Osco            203       8.17
      8    antacid           Osco            206       7.50
      9    antacid           Osco            207       9.02
     10    antacid           Osco            208       7.56
     11    antacid           Osco            210       9.23
     12    antacid           Target          305       8.25
     13    antacid           Target          306       8.10
     14    antacid           Target          308       6.73
     15    antacid           Target          311       9.11
     16    antacid           Target          313       8.61
     17    antacid           Target          314       7.67
     18    antacid           Target          315       8.42
     19    antacid           Walgreens       406       7.91
     20    antacid           Walgreens       407       7.48
     21    antacid           Walgreens       413       8.82
     22    antacid           Walgreens       415       8.50
     23    antacid           Walgreens       417       6.89
     24    antacid           Walgreens       424       8.32
     25    antacid           Walgreens       426       8.22
     26    aspirin           CVS             101       4.37
     27    aspirin           CVS             103       6.57
     28    aspirin           CVS             104       5.58
     29    aspirin           CVS             105       7.02
     30    aspirin           Osco            203       4.63
     31    aspirin           Osco            205       3.60
     32    aspirin           Osco            208       5.38
     33    aspirin           Osco            210       6.66
     34    aspirin           Target          305       5.08
     35    aspirin           Target          306       5.11
     36    aspirin           Target          308       3.95
     37    aspirin           Target          311       6.08
     38    aspirin           Target          313       5.35
     39    aspirin           Target          315       3.78
     40    aspirin           Walgreens       406       3.60
     41    aspirin           Walgreens       407       6.16
     42    aspirin           Walgreens       415       6.98
     43    aspirin           Walgreens       417       4.16
     44    aspirin           Walgreens       424       4.69
     45    aspirin           Walgreens       426       5.44
     46    cough medicine    CVS             101       7.86
     47    cough medicine    CVS             102       5.85
     48    cough medicine    CVS             103       7.82
     49    cough medicine    CVS             104       6.48
     50    cough medicine    CVS             105       7.20

                       Drugstore1 Dataset                      2

    Obs       product        chain        store_id    price

     51    cough medicine    Osco            203       5.68
     52    cough medicine    Osco            206       6.68
     53    cough medicine    Osco            207       5.24
     54    cough medicine    Osco            208       4.73
     55    cough medicine    Osco            210       3.53
     56    cough medicine    Osco            213       5.65
     57    cough medicine    Target          305       3.96
     58    cough medicine    Target          306       5.59
     59    cough medicine    Target          308       6.11
     60    cough medicine    Target          311       7.09
     61    cough medicine    Target          315       4.96
     62    cough medicine    Walgreens       406       5.40
     63    cough medicine    Walgreens       407       6.46
     64    cough medicine    Walgreens       413       6.94
     65    cough medicine    Walgreens       415       5.15
     66    cough medicine    Walgreens       424       6.15
     67    cough medicine    Walgreens       426       3.46

                       Drugstore1 Dataset                      3

 Mean of price
 „ƒƒƒƒƒƒƒƒ…ƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒ†
 ‚        ‚                       chain                       ‚
 ‚        ‡ƒƒƒƒƒƒƒƒƒƒƒƒ…ƒƒƒƒƒƒƒƒƒƒƒƒ…ƒƒƒƒƒƒƒƒƒƒƒƒ…ƒƒƒƒƒƒƒƒƒƒƒƒ‰
 ‚        ‚    CVS     ‚    Osco    ‚   Target   ‚ Walgreens  ‚
 ‡ƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒ‰
 ‚product ‚            ‚            ‚            ‚            ‚
 ‡ƒƒƒƒƒƒƒƒ‰            ‚            ‚            ‚            ‚
 ‚antacid ‚       10.89‚        8.29‚        8.13‚        8.02‚
 ‡ƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒ‰
 ‚aspirin ‚        5.89‚        5.07‚        4.89‚        5.17‚
 ‡ƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒˆƒƒƒƒƒƒƒƒƒƒƒƒ‰
 ‚cough   ‚            ‚            ‚            ‚            ‚
 ‚medicine‚        7.04‚        5.25‚        5.54‚        5.59‚
 Šƒƒƒƒƒƒƒƒ‹ƒƒƒƒƒƒƒƒƒƒƒƒ‹ƒƒƒƒƒƒƒƒƒƒƒƒ‹ƒƒƒƒƒƒƒƒƒƒƒƒ‹ƒƒƒƒƒƒƒƒƒƒƒƒŒ