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A bakery records how many minutes 24 online orders took to be ready, on a made-up day…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A bakery records how many minutes 24 online orders took to be ready, on a made-up day. The times are , , , , and . First use bins 10 minutes wide starting at 10. How many orders fall in the bin 30 to 40? Then use bins 20 minutes wide starting at 5: 5 to 25, 25 to 45 and 45 to 65. Give the three counts. Which histogram tells the truth about two kinds of order, and why does the other one hide it?
Need a reminder? The key ideaShow
The worked solution
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Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The narrow bins. With width 10 from 10 the counts are 6, 8, 0, 6 and 4. No order took between 30 and 40 minutes, so that bar is empty.
Step 2. The wide bins. From 5 to 25 there are 10 orders: up to . From 25 to 45 there are 7: , . From 45 to 65 there are 7: up to .
Answer: 0 orders; then 10, 7 and 7.
Which tells the truth? The narrow bins show two clusters with an empty gap between them: perhaps ready-made cakes and cakes baked to order. The wide middle bin joins the top of one cluster to the bottom of the other. The gap falls inside one bar, and the picture looks like a single hill with a tail.
Lesson. Before you describe a shape, try more than one bin width and more than one start.
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