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MMathematicsS4 to S6Industry

Industry lab: quality control in a juice factory

Every bottle should contain at least what the label says, but filling machines are never perfect. Use statistics to keep a factory’s quality high and its waste low.

mean ± 3σ/√n500 mL
LevelS4 to S6 (and A Level)
TimeAbout 40 min
You useMean, standard deviation, normal distribution
PriceFree: no account

🎯 Aim

To use sampling, the normal distribution and control charts to monitor a filling machine in a factory.

You will learn to

  • Calculate the mean and standard deviation of a sample.
  • Use the normal distribution (68–95–99.7 rule).
  • Set a machine so few bottles are underfilled.
  • Use a control chart to detect a fault.

🧭 What to do

  1. Tap Take a sample of 5 bottles (1 hour) several times and watch the control chart.
  2. Tap Run 8 hours and look at the histogram.
  3. Change the Target volume (mean) and the Spread of the machine: read the bottles below 500 mL.
  4. Choose Drifts down 0.6 mL per hour and find when the chart shows the fault.
  5. Answer the questions with the class data.
  6. Write your conclusion and download your lab report.

🔬 Lab bench

📋 The data

Volumes of 5 bottles sampled in two hours.

🧠 Investigate: answer from the data

Type your answer and tap Check. Use 💡 Hint first; open the method only when you are stuck.

📄 My lab report

Your report collects the aim, your data table, the graphs, your answers and your conclusion. It is made on your phone or computer: nothing is sent to anyone.

Check your conclusion

Bottle volumes follow a normal distribution: about 95 % lie within two standard deviations of the mean. To keep few bottles below the label, the mean is set above 500 mL; a machine with a smaller spread can be set closer and wastes less juice. Means of small samples plotted on a control chart show a drift or fault early, before many bad bottles are made.

➕ Get more from this experiment

📝 Free

Print the worksheet (button above), download the data, and save your report. Teachers can project this page in class.

📦 Premium Lab Pack

1 000 RWF

  • Worksheet: measure and analyse real drink or water bottles
  • Statistics and control chart problems
  • Teacher guide and answer key
  • Exam-style questions with marking scheme

👩‍🏫 For teachers

Use it as a practical when apparatus is missing, as homework, or as a project. Free lesson plans help you plan, teach and assess.

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DONAT STEM Interactive Labs · original work by BIZIYAREMYE Donat · data are realistic models for learning · free forever