Mean and median worksheets for Grade 9 Computer Science help students calculate measures of central tendency and investigate how extreme values affect the interpretation of numerical data. Using computer program response times and processing measurements, this resource connects data analysis concepts to practical computing examples while building accurate calculation and reasoning skills.

Students explore how the arithmetic mean summarizes values using their total and the number of observations, while the median identifies the middle value in an ordered data set. They also examine why these measures can differ and how an unusually large observation, or outlier, can influence the mean more strongly than the median.

From Calculation to Data Interpretation

The worksheet moves beyond memorizing formulas. Students practise applying each method, checking their results and explaining which measure provides a more useful representation of typical performance. The reading passage uses program response times of 4, 5, 5, 6 and 10 milliseconds to demonstrate a mean of 6 milliseconds and a median of 5 milliseconds. A further example introduces an extreme response time of 50 milliseconds to illustrate its effect on the mean.

Throughout the activities, learners develop practical skills in numerical data analysis, including:

• Calculating the arithmetic mean: Add all observations and divide the sum by the number of values.
• Finding the median: Arrange values in ascending order, select the middle value for an odd-sized data set, or average the two middle values for an even-sized set.
• Comparing measures of central tendency: Explain why the mean and median may differ and evaluate the influence of outliers.
• Interpreting computing data: Apply calculations to response times and processing times to describe program performance.

What Students Practise

Students work through a connected mix of learning activities: a dialogue, definition matching, a fill-in-the-blank cloze passage, a diagram-labeling task and a reading comprehension passage. Multiple-choice questions assess formula knowledge, numerical calculations and method selection. True-or-false statements check common misconceptions, including the incorrect practice of always selecting the larger middle value for an even-sized data set.

Short-answer exercises require students to show calculations and explain their reasoning. An extended-response task brings the concepts together by asking students to calculate and compare the mean and median of program processing times, discuss the influence of an extreme value, justify their choice of a representative measure and identify a situation where the mean would be useful.

Included Resource and Teacher Support

• Student worksheet: A structured sequence of activities covering definitions, calculations, reading, data interpretation and written explanations.
• Separate teacher guide PDF: Includes learning objectives, teaching tips, discussion questions and common mistakes to support lesson preparation and classroom instruction.

Practical Classroom Uses

Use this Grade 9 data and information activity during a lesson on numerical data analysis, as guided practice after introducing mean and median, or as independent work to reinforce calculation methods. The reading passage provides a shared example for class discussion, while the written responses give students opportunities to justify their conclusions rather than simply select answers.

For teachers covering introductory statistics within computer science, this printable practice resource connects mathematical reasoning with the interpretation of computing measurements. It helps learners recognise that choosing a suitable summary depends on the distribution of the data and the presence of extreme observations. The resource is identified under the general framework, without claiming alignment to a specific curriculum standard.