5.0 Data Handling and Probability

5.1 Data Interpretation (Grouped Data) - Determining appropriate class width for grouping data

By the end of the lesson, the learner should be able to:
- Define class and class width
- Determine appropriate class width from given range of data
- Appreciate the importance of grouping data with many values

The learner is guided to:
- Choose numbers between 1 and 100 and find the range
- Divide the range into equal intervals or classes
- Discuss the width of classes selected
- Compare class widths with other groups

How do we group data with many values?

- Master Mathematics Grade 9 pg. 224
- Writing materials
- Calculators
- Chart papers
- Digital devices

- Observation - Oral questions - Written assignments

5.0 Data Handling and Probability

5.1 Data Interpretation (Grouped Data) - Drawing frequency distribution tables of grouped data

By the end of the lesson, the learner should be able to:
- Explain the components of a frequency distribution table
- Draw frequency distribution tables for grouped data using tally marks
- Show interest in organizing data systematically

The learner is guided to:
- Discuss suitable class width for given data
- Represent data in each class using tally marks
- Count tally marks and record as frequency
- Complete frequency distribution tables

How do we organize grouped data in tables?

- Master Mathematics Grade 9 pg. 226
- Tally sheets
- Rulers
- Data sets
- Pencils

- Class activities - Written tests - Observation

5.0 Data Handling and Probability

5.1 Data Interpretation (Grouped Data) - Identifying the modal class of grouped data

By the end of the lesson, the learner should be able to:
- Define mode, modal frequency and modal class
- Identify the modal class from frequency distribution tables
- Appreciate identifying the class with highest frequency

The learner is guided to:
- Prepare frequency distribution tables for given data
- Identify the highest frequency from the table
- Find the class where the highest frequency lies
- Search for the meaning of mode using digital devices

What is the modal class in grouped data?

- Master Mathematics Grade 9 pg. 228
- Frequency distribution tables
- Digital devices
- Reference materials

- Oral questions - Written assignments - Class activities

5.0 Data Handling and Probability

5.1 Data Interpretation (Grouped Data) - Calculating the mean of grouped data (1)

By the end of the lesson, the learner should be able to:
- Explain the process of finding mean of grouped data
- Calculate midpoints of classes
- Show interest in organizing data to find the mean

The learner is guided to:
- Group given data into classes
- Add class limits and divide by 2 to get midpoints
- Work out products of midpoints and frequencies (fx)
- Find the sum of fx values

How do we find the mean of grouped data?

- Master Mathematics Grade 9 pg. 230
- Calculators
- Frequency tables
- Writing materials

- Observation - Written tests

5.0 Data Handling and Probability

5.1 Data Interpretation (Grouped Data) - Calculating the mean of grouped data (2)

By the end of the lesson, the learner should be able to:
- State the formula for calculating mean of grouped data
- Apply the formula mean = Σfx/Σf to solve problems
- Appreciate using the Greek symbol Σ in mathematics

The learner is guided to:
- Arrange tables to include midpoint and fx columns
- Calculate Σf and Σfx
- Apply the formula to determine mean
- Solve problems involving mean of grouped data

How do we apply the mean formula to grouped data?

- Master Mathematics Grade 9 pg. 230
- Mathematical tables
- Calculators
- Data sets
- Charts

- Class activities - Written assignments - Oral questions