**13. **STATISTICS

**MAX MARKS: – 12**

**TIME- 1 H **

**1.The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is Rs.18. Find the missing frequency f.**

Daily pocket allowance (in Rs) | 11 − 13 | 13 − 15 | 15 −17 | 17 − 19 | 19 − 21 | 21 − 23 | 23 − 25 |

Number of workers | 7 | 6 | 9 | 13 | f | 5 | 4 |

**2.In a retail market, fruit vendors were selling mangoes kept in packing boxes. These boxes contained varying number of mangoes. The following was the distribution of mangoes according to the number of boxes.Find the mean number of mangoes kept in a packing box. Which method of finding the mean did you choose?**

Number of mangoes | 50 − 52 | 53 − 55 | 56 − 58 | 59 − 61 | 62 − 64 |

Number of boxes | 15 | 110 | 135 | 115 | 25 |

**3.The following data gives the information on the observed lifetimes (in hours) of 225 electrical components**, **Determine the modal lifetimes of the components.**

Lifetimes (in hours) | 0 − 20 | 20 − 40 | 40 − 60 | 60 − 80 | 80 − 100 | 100 − 120 |

Frequency | 10 | 35 | 52 | 61 | 38 | 29 |

**4. If the median of the distribution is given below is 28.5, find the values of x and y.**

Class interval | Frequency |

0 − 10 | 5 |

10 − 20 | x |

20 − 30 | 20 |

30 − 40 | 15 |

40 − 50 | y |

50 − 60 | 5 |

Total | 60 |