Example 2

13.3.3 Example 2

Description

Quick Overview

This section describes how to find the mode of a dataset and compares it with the mean.

Standard

In this section, we learn how to calculate the mode from the distribution of students' examination marks and analyze the difference between the mode and mean. This concept helps in understanding the frequency and central tendency in a dataset.

Detailed

In this example, we are provided with the marks distribution of 30 students in a mathematics examination. We are tasked with finding the mode of this dataset based on the provided frequency table. The modal class, being the interval where the maximum number of students scored, is identified as 40 - 55 where 7 students scored. We then apply the mode formula:

Mode = l + ( (f1 - f0)/(2f1 - f0 - f2) ) * h.
Substituting the values: l = 40, h = 15, f1 = 7 (frequency of the modal class), f0 = 3 (preceding class frequency), and f2 = 6 (succeeding class frequency), we compute the mode as 52. The section further contrasts the mode with the mean, where the mean is stated to be 62. This encourages critical thinking about the context of data representation β€” whether we seek an average unique to most students (mode) or typical overall performance (mean).

Key Concepts

  • Mode: Defines the most frequently occurring value in a dataset.

  • Mean: The average value determined by adding all numbers and dividing by the count.

  • Modal Class: The interval with the greatest frequency.

  • Frequency: How often a particular value appears in a dataset.

Memory Aids

🎡 Rhymes Time

  • Find the mode, don't be slow, it’s the score that we all know!

πŸ“– Fascinating Stories

  • Imagine a classroom where students scored mostly 52 in exams. They often averaged 62, showing some struggled, while others excelled; the tale of both scores tells us much!

🧠 Other Memory Gems

  • M.O.D.E: Most Often Data’s Elected.

🎯 Super Acronyms

M for Most, O for Often, D for Data, E for Elected.

Examples

  • In a class test, 7 students scored between 40 and 55 marks, indicating this range as the modal class.

  • Given the mean score is 62, the mode being 52 indicates a significant insight into students' performance.

Glossary of Terms

  • Term: Mode

    Definition:

    The value that appears most frequently in a data set.

  • Term: Mean

    Definition:

    The average of all values in a data set, calculated by dividing the sum of all values by the number of values.

  • Term: Modal Class

    Definition:

    The interval in a frequency distribution that contains the highest frequency.

  • Term: Frequency

    Definition:

    The number of times a value or range of values occurs in a data set.

  • Term: Class Size

    Definition:

    The range of values in a given class interval in a frequency distribution.