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#### Question

Thirty women were examined in a hospital by a doctor and the number of heart beats per minute were recorded and summarized as follows. Fine the mean heart beats per minute for these women, choosing a suitable method.

Number of heart beats per minute | 65 − 68 | 68 − 71 | 71 −74 | 74 − 77 | 77 − 80 | 80 − 83 | 83 − 86 |

Number of women | 2 | 4 | 3 | 8 | 7 | 4 | 2 |

#### Solution

#### Similar questions

The table below shows the daily expenditure on food of 25 households in a locality.

Daily expenditure (in Rs) | 100 − 150 | 150 − 200 | 200 − 250 | 250 − 300 | 300 − 350 |

Number of households | 4 | 5 | 12 | 2 | 2 |

Find the mean daily expenditure on food by a suitable method.

A survey was conducted by a group of students as a part of their environment awareness programme, in which they collected the following data regarding the number of plants in 20 houses in a locality. Find the mean number of plants per house.

Number of plants | 0 - 2 | 2 - 4 | 4 - 6 | 6 - 8 | 8 - 10 | 10 - 12 | 12 - 14 |

Number of houses | 1 | 2 | 1 | 5 | 6 | 2 | 3 |

Which method did you use for finding the mean, and why?

The measurements (in mm) of the diameters of the head of the screws are given below:

Diameter (in mm) | No. of Screws |

33 — 35 | 10 |

36 — 38 | 19 |

39 — 41 | 23 |

42 — 44 | 21 |

45 — 47 | 27 |

Calculate mean diameter of head of a screw by ‘Assumed Mean Method’.

The following table gives the frequency distribution of trees planted by different Housing Societies in a particular locality:

No. of Trees | No. of Housing Societies |

10-15 | 2 |

15-20 | 7 |

20-25 | 9 |

25-30 | 8 |

30-35 | 6 |

35-40 | 4 |

Find the mean number of trees planted by Housing Societies by using ‘Assumed Means Method’

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.

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

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

Find the mean number of mangoes kept in a packing box. Which method of finding the mean did you choose?