Option 2 : 2

Group X 2021 Full Mock Test

83247

70 Questions
70 Marks
60 Mins

Standard deviation \(= \sqrt {\frac{{{\rm{\Sigma }}{{\left( {x - \bar x} \right)}^2}}}{N}} \)

Where, \(\bar x\) is the mean of the data

and N is the number of terms

\(\bar x = {\Sigma \left( {x } \right)/N}\)

\(= {\frac{{{{\left( 11+7+10+13+9 \right)}}}}{5}} \)

\(\bar x = 10\)

x |
11 |
7 |
10 |
13 |
9 |

\({\left( {x - \bar x} \right)^2}\) |
1 |
9 |
0 |
9 |
1 |

\({\rm{\Sigma }}{\left( {x - \bar x} \right)^2} = 1 + 9 + 0 + 9 + 1 = 20\)

∴ Standard deviation = √(20/5) = √4 = 2