Correct option is : (3) 7
| x |
C |
2C |
3C |
4C |
5C |
6C |
| f |
2 |
1 |
1 |
1 |
1 |
1 |
\(\bar{x}=\frac{(2+2+3+4+5+6) C}{7}=\frac{22 C}{7}\)
\(\operatorname{Var}(\mathrm{x})=\frac{\mathrm{c}^{2}\left(2+2^{2}+3^{2}+4^{2}+5^{2}+6^{2}\right)}{7}\)
\(-\left(\frac{22 c}{7}\right)^{2}\)
\(=\frac{92 c^{2}}{7}-c^{2} \times \frac{484}{49}\)
\(=\frac{(644-484) \mathrm{c}^{2}}{49}=\frac{160 \mathrm{c}^{2}}{49}\)
\(160=\frac{160 \times \mathrm{c}^{2}}{49} \Rightarrow \mathrm{c}=7\)
