Class 11

Math

JEE Main Questions

Statistics

Find the mean and variance for the following frequency distributions :

The following frequency distribution gives the monthly consumption of electricity of $68$ consumers of a locality. Find the median, mean and mode of the data and compare them.

Monthly consumption (in units): | $65−85$ | $85−105$ | $105−125$ | $125−145$ | $145−165$ | $165−185$ | $185−205$ |

No. of consumers | $4$ | $5$ | $13$ | $20$ | $14$ | $8$ | $4$ |

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: | $4$ | $5$ | $12$ | $2$ | $2$ |

The distribution below gives the weights of $30$ students of a class. Find the median weight of the students.

Weight (in kgs) | $40−45$ | $45−50$ | $50−55$ | $55−60$ | $60−65$ | $65−70$ | $70−75$ |

Number of students | $2$ | $3$ | $8$ | $6$ | $6$ | $3$ | $2$ |

Calculate the missing frequency from the following distribution, it being given that the median of the distribution is $24$.

Class | $0−10$ | $10−20$ | $20−30$ | $30−40$ | $40−50$ |

Frequency | $5$ | $25$ | $?$ | $18$ | $7$ |