class 11

Math

Algebra

Statistics

Algebraic sum of all the deviation from 30 of 50 observations is 50. Find their mean (A) $20$ (B) $30$ (C) $80$ (D) $31$

Similar Topics

determinants

matrices

binomial theorem

complex numbers and quadratic equations

sequences and series

Find the mean deviation about the mean for the data

Height of cms | Number of boys |

95-105 | 9 |

105-115 | 13 |

115-125 | 26 |

125-135 | 30 |

135-145 | 12 |

145-155 | 10 |

Find the mean and standard deviation using short-cut method

$X_{i}$ | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 |

$f_{i}$ | 2 | 1 | 12 | 29 | 25 | 12 | 10 | 4 | 5 |