# CBSE Class 10-Mathematics: Chapter –14 Statistics Part 14

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**Question 9:**

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

Number of heart beats per minute | No. of women |

**Answer:**

Let assumed mean . We have

No. of heart beats per minute | No. of women | Class Mark mid value | ||

We know that

Mean [By step Deviation Method]

**Question 10:**

Following distribution shows the marks obtained by a class of students:

Marks | ||||||

Frequency |

Change the distribution to less than type distribution and draw its O give.

**Answer:**

Less than type O give

Marks | Marks | Frequency | Cumulative Frequency |

Less than 20 | |||

Less than 30 | |||

Less than 40 | |||

Less than50 | |||

Less than 60 | |||

Less than 70 |

Now, draw the Ogive by plotting