Four groups of students recorded their pulse rates after a 2 km run. Group 1 126 168 158 192 146 166 104 164 1 16 138 172 Group 2 136 158 132 152 156 128 160 108 150 178 136 172 140 Group 3 126 154 136 174 130 156 160 176 150 166 142 156 130 182 180 Group 4 166 144 150 148 142 172 152 174 176 118 152 178 164 128 158 158 166 Determine the standard deviation of Group 4, to one decimal place