## Mathematics TERM II

## Statistics

## Class 10 Session 2021-2022

## Case Study Questions 01

**Student-Teacher Ratio:** Student-teacher ratio expresses the relationship between the number of students enrolled in a school and the number of teachers in that school. It is important for a number of reasons. For example, it can be an indicator of the amount of individual attention any child is likely to receive, keeping in mind that not all class size are going to be the same.

The following distribution gives the state-wise student-teacher ratio in higher secondary schools of India (28 states and

7 UTs only).

Number of students per teacher | Number of States/UTs |
---|---|

15-20 | 3 |

20-25 | 8 |

25-30 | 9 |

30-35 | 10 |

35-40 | 3 |

40-45 | 0 |

45-50 | 0 |

50-55 | 2 |

1. In order to find the mean by direct method, we use the formula

(a) `\frac{\sum_{i=1}^n f_{i}x_{i}}{n}`

(b) `\frac{n}{\sum_{i=1}^n f_{i}x_{i}}`

(c) `n\times \sum_{i=1}^n f_{i}x_{i}`

(d) `n+\sum_{i=1}^n f_{i}x_{i}`

(a) `\frac{\sum_{i=1}^n f_{i}x_{i}}{n}`

2. The mean of the above data is

(a) 29.2

(b) 30.5

(c) 38.3

(d) 40.1

(a) 29.2

3. The formula for assumed mean method to find the mean is

(a) `A-\frac{\sum f_{i}d_{i}}{\sum f_{i}}`

(b) `A+\frac{\sum f_{i}}{\sum f_{i}d_{i}}`

(c) `A\times\frac{\sum f_{i}d_{i}}{\sum f_{i}}`

(d) `A+\frac{\sum f_{i}d_{i}}{\sum f_{i}}`

(d) `A+\frac{{\sum}f_{i}d_{i}}{\sum f_{i}}`

4. The sum of class marks of 25-30 and 45-50 is

(a) 62

(b) 70

(c) 75

(d) 85

(c) 75

5. The sum of the upper and lower limits of modal class is

(a) 55

(b) 65

(c) 85

(d) 75

(b) 65