Reach for the Star

Averages and spread · Optional extension

L047 · Allow 10–15 minutes for learners ready to move on. Answers are available after an attempt.

Stretch

Five numbers have mean 12. Four are 8, 11, 13 and 15. Find the fifth and the range.

Reveal a worked check after attempting

Total=60; fifth=13; range=15−8=7.

Deep challenge

A data set has mean 10. One new value of 100 is added. Must the median increase?

Reveal a worked check after attempting

No. A high outlier increases the mean, but the middle ordered value may stay the same.

Recall & Review: feedback and extension integration

Lesson L047: Averages and spread

Objective: Calculate and interpret averages and range, including grouped estimates.

60-minute structure: 0-7 Connect & Check; 7-14 Share; 14-25 Present/model; 25-44 Apply route choice/practice; 44-52 independent exam-style check; 52-60 Recall & Review, WWW/EBI and next step.

What Went Well (WWW)

I selected an appropriate statistic or representation and supported my comparison or interpretation with specific evidence from the data.

Even Better If (EBI)

I will quote the relevant values or features, compare like with like and explain what the evidence shows without making an unsupported claim.

Stretch and deep challenge

Stretch: Five numbers have mean 12. Four are 8, 11, 13 and 15. Find the fifth and the range.

Deep challenge: A data set has mean 10. One new value of 100 is added. Must the median increase?