Answer the following questions on the basis of the given data :

Marks |
10 | 20 | 30 | 40 | 50 |

No. of Students |
4 | 7 | 13 | 8 | 6 |

1) Write the formula of Q_{1} and Q_{3}.

2) Find out the median of the above data?

3) Find out the cumulative frequency of the last value in the above data.

4) Find out the value of 'n' in the above data

Marks |
No. of Students |
cf |

10 | 4 | 4 |

20 | 7 | 11 |

30 | 13 | 24 |

40 | 8 | 32 |

50 | 6 | 38 |

N = 38 |

1. Formula of Q_{1}

Q_{1 }= Size of 1

Formula of Q_{3}

Q_{3 }= Size of 3

2. Median = Q_{2}

Median = Q_{2 }= Size of 2

_{ }= Size of 2

_{ }= Size of 2

= Size of 2 (9.75)^{th} observation

= Size of 19.5^{th} observation

= Size of 19.5^{th} observation lies in cf 24

Hence, quartile value = 30 marks.

3. The cumulative frequency of the last value in the above data is 38.

4. The value of 'n' in the above data is 38.