# Ex.14.2 Q9 Statistics Solution - NCERT Maths Class 9

Go back to 'Ex.14.2'

## Question

A company manufactures car batteries of a particular type. The lives (in years) of \(40\) such batteries were recorded as follows:

\(2.6\) | \(3.0\) | \(3.7\) | \(3.2\) | \(2.2\) | \(4.1\) | \(3.5\) | \(4.5\) |

\(3.5\) | \(2.3\) | \(3.2\) | \(3.4\) | \(3.8\) | \(3.2\) | \(4.6\) | \(3.7\) |

\(2.5\) | \(4.4\) | \(3.4\) | \(3.3\) | \(2.9\) | \(3.0\) | \(4.3\) | \(2.8\) |

\(3.5\) | \(3.2\) | \(3.9\) | \(3.2\) | \(3.2\) | \(3.1\) | \(3.7\) | \(3.4\) |

\(4.6\) | \(3.8\) | \(3.2\) | \(2.6\) | \(3.5\) | \(4.2\) | \(2.9\) | \(3.6\) |

Construct a grouped frequency distribution table for this data, using class Intervals of size \(0.5\) starting from the interval \(2 - 2.5.\)

## Text Solution

**What is known?**

- The life span (in years) of \(40\) car batteries manufactured by a company.
- Class size is ‘\(0.5\)’
- A class interval such as \(2-2.5\)

**What is unknown?**

- Constructing a grouped frequency distribution table with a class size of \(0.5.\)

**Steps:**

The required grouped frequency distribution table can be constructed as follows, with class intervals of ‘\(2-2.5\)’, ‘\(2.5-3\)’, ‘\(3-3.5\)’, ‘\(3.5-4\)’, and so on.

LIFE SPAN OF BATTERIES (in years) |
NUMBER OF BATTERIES (frequency) |

\(2-2.5 \) | \(2\) |

\(2.5-3.0 \) | \(6 \) |

\(3.0-3.5\) | \(14 \) |

\(3.5-4.0 \) | \(11 \) |

\(4.0-4.5 \) | \(4 \) |

\(4.5-5.0\) | \(3\) |

TOTAL |
\(40\) |