7 The heights, in cm, of the 11 members of the Anvils athletics team and the 11 members of the Brecons swimming team are shown below.
| Anvils | 173 | 158 | 180 | 196 | 175 | 165 | 170 | 169 | 181 | 184 | 172 |
| Brecons | 166 | 170 | 171 | 172 | 172 | 178 | 181 | 182 | 183 | 183 | 192 |
- Draw a back-to-back stem-and-leaf diagram to represent this information, with Anvils on the left-hand side of the diagram and Brecons on the right-hand side.
- Find the median and the interquartile range for the heights of the Anvils.
The heights of the 11 members of the Anvils are denoted by \(x \mathrm {~cm}\). It is given that \(\Sigma x = 1923\) and \(\Sigma x ^ { 2 } = 337221\). The Anvils are joined by 3 new members whose heights are \(166 \mathrm {~cm} , 172 \mathrm {~cm}\) and 182 cm . - Find the standard deviation of the heights of all 14 members of the Anvils.
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