More on describing data by pictures and neumerical summaries (brain weight data)
> brainwt[sex == "f"]
 [1] 1125 1027 1112  983 1090 1247 1045  983  972 1045  937 1245 1200 1270 1200 1145 1090 1040
[19] 1343 1010 1095 1180 1168 1095 1040 1235 1050 1038 1046 1255 1228 1000 1225 1220 1085 1067
[37] 1006 1138 1175 1252 1037  958 1020 1068 1107 1317  952 1056 1203 1183 1392 1130 1284  996
[55] 1228 1087 1035 1170 1064 1250 1129 1088 1037 1117 1095 1027 1027 1190 1153 1037 1120 1212
[73] 1024 1135 1177 1096 1114
> length(brainwt[sex == "f"])
[1] 77
> sort(brainwt[sex == "f"])
 [1]  937  952  958  972  983  983  996 1000 1006 1010 1020 1024 1027 1027 1027 1035 1037 1037
[19] 1037 1038 1040 1040 1045 1045 1046 1050 1056 1064 1067 1068 1085 1087 1088 1090 1090 1095
[37] 1095 1095 1096 1107 1112 1114 1117 1120 1125 1129 1130 1135 1138 1145 1153 1168 1170 1175
[55] 1177 1180 1183 1190 1200 1200 1203 1212 1220 1225 1228 1228 1235 1245 1247 1250 1252 1255
[73] 1270 1284 1317 1343 1392
> quantile(brainwt[sex == "f"])
  0%  25%  50%  75% 100% 
 937 1038 1096 1190 1392 
> # you can see that median (50th-perc) value 1096 is the 39th obs in size, 38 below and above
> # 1038 is the 20th obs in size, 1190 is the 58th obs in size, both just about median of halfs
> stem(brainwt[sex == "f"])

  The decimal point is 2 digit(s) to the right of the |

   9 | 4
   9 | 56788                    > # very first line is smallest value stem 9 leaf 4       
  10 | 0011223334444444              representing 937 (think 9.40 and move               
  10 | 5555667799999            > # decimal point 2 places as indicated to read 940) and 
  11 | 00001112233344              so forth. 952 is stem 9 leaf 5 etc                    
  11 | 557788889
  12 | 000123334
  12 | 5555678
  13 | 24
  13 | 9


> mean(brainwt[sex == "f"]);sd(brainwt[sex == "f"])
[1] 1117.169
[1] 98.97094
> mean(brainwt[sex == "f"]+ 7);sd(brainwt[sex == "f"]+7)
[1] 1124.169
[1] 98.97094
> mean(brainwt[sex == "f"]/3);sd(brainwt[sex == "f"]/3)
[1] 372.3896
[1] 32.99031