Statistical Measures

Using the Range

Stem and Leaf Diagrams

Mean from a Frequency Table

Mean from a Grouped Data

Esimating the Mean from Grouped Data

Prerequisite Knowledge

• Interpret and present discrete and continuous data using appropriate graphical methods, including bar charts and time graphs.
• Solve comparison, sum and difference problems using information presented in bar charts, pictograms, tables and other graphs.

Success Criteria

• Interpret, analyse and compare the distributions of data sets from univariate empirical distributions through:
• Appropriate graphical representation involving discrete, continuous and grouped data
• Appropriate measures of central tendency (median, mean, mode and modal class) and spread
• Construct and interpret stem and leaf diagrams
• Apply statistics to describe a population

Key Concepts

• A frequency table is used when the sample size increases beyond simple calculations being possible from a list.
• The median average of a class width is used as the mid-pint when calculating the mean from grouped data.

Common Misconceptions

• Students often find it difficult to calculate the median average from data presented in a frequency table.
• When sorting continuous data into a grouped data table students often struggle to fully understand the inequality notation.