Grouping Data With Histograms

Grouping Data With Histograms

Year 8 Mathematics Understanding and Creating Histograms Interpreting Continuous Data

Starter Activity: Compare These Graphs

Look at the two graphs displayed List 3 similarities between them List 3 differences between them Discuss with your partner

Learning Intentions

Learn that frequency tables and histograms can be used to display data Construct frequency tables and histograms Draw conclusions from histograms

Success Criteria

I can construct frequency tables from raw data I can draw histograms using frequency tables I can interpret information from histograms I can identify the modal class

What is Frequency?

Frequency is the number of times a particular event appears in a data set

Understanding Continuous Data

Continuous data can take any value within a range Examples: height, weight, time, temperature Different from discrete data (whole numbers only) Can be measured to any level of precision

Continuous vs Discrete Data

{"left":"Height (can be 165.3cm, 165.37cm)\nWeight (can be 65.2kg, 65.25kg)\nTime (can be 12.5 seconds, 12.53 seconds)","right":"Number of students (1, 2, 3, 4...)\nNumber of pets (0, 1, 2, 3...)\nShoe size (7, 8, 9, 10...)"}

What are Intervals?

Data is grouped into equal intervals Examples: 10-19, 20-29, 30-39 Intervals should be equal in size Choose sensible intervals for your data

Practice: Creating Intervals

Data set: Ages 15, 23, 31, 18, 27, 35, 19, 24, 29, 33 Create appropriate intervals for this data Make sure intervals are equal in size Work with your partner

Constructing Frequency Tables

Step 1: Determine appropriate intervals Step 2: Create tally marks for each data point Step 3: Count tallies to find frequency Step 4: Check total frequency matches data count

Frequency Table Example

Create Your Own Frequency Table

Use the time data provided Times (seconds): 18, 22, 27, 31, 35, 19, 24, 28, 33, 37, 20, 25, 29, 34, 21 Create intervals: 15-20, 20-25, 25-30, 30-35, 35-40 Complete the frequency table