# Seedy CDs

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### Bar chart showing the number of CDs sold in a week

What is the total number of CDs sold during the week?

What is the mode and mean?

What is the range of sales?

Sketch a similar bar chart showing Tuesday as the best sales day and the mean and range both 4.

## A Mathematics Lesson Starter Of The Day

Topics: Starter | Averages | Graphs | Statistics

• Mr Gray, Oldmachar
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• Would have been a good activity but we couldn't get the whole graph displayed on the screen/white board
• Transum,
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• Thanks for your feedback Mr Gray. The graph is designed to be as big as possible while still fitting on an 800x600 screen. If you are using Internet Explorer press the F11 key to hide the toolbars. If they don't all disappear you may need to right click and choose autohide.
• Karen, Folkestone
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• Have used and is a good starter, however blue does not display well in my classroom - any chance of option to change colour?
• Mr Taylor, Gartree High School
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• Hi, I think that the part of the starter about mode in incorrect- but perhaps you could correct me if I'm mistaken.
The graph we saw was somthing like Mon:8 Tues:2 Wed:6 Thurs:8 Fri:2 Sat:4 Sun:2 and in the answers they say that the "modal days" are Monday and Thursday. It's true that the maximum number of CDs were sold on Monday and Thursday, but the mode is a type of average just like the mean (and the mode of a data set is the data item that occurs most frequently). The most frequently occuring amount is two; so it would be correct to say that the "modal number of CDs sold" was 2. Modal day wouldn't really make sense in this context since the days of the week aren't the thing being counted.
• Transum,
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• Thanks Karen and Mr Taylor for your comments. The colour scheme has been changed and the error with the mode corrected. Your feedback is much appreciated.
• Mr Jackson, Saint Bedes Redhill
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• My year 7's really enjoyed this starter it made them think, thank you.
• Jordan, Year 6 Charnwood Primary School, Lichfield
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• This was really good. Most people remembered mode, mean and range.
• Gillian Miskell, Picton, NZ
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• I would love to see something like this but with dot plots, as we use those extensively to lead on to box and whisker.
• Transum,
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• For another interesting bar chart click on one of the gold stars below. After a second or two a bar chart will be drawn showing the distribution of votes for this starter.
• Kelly, North Carolina
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• The graph should be able to be moved on a touch screen.

How did you use this starter? Can you suggest how teachers could present or develop this resource? Do you have any comments? It is always useful to receive feedback and helps make this free resource even more useful for Maths teachers anywhere in the world.

Previous Day | This starter is for 12 September | Next Day

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### Bar Chart showing the number of CDs sold in a week

Here is one possible bar chart meeting the criteria. There are others. Tuesday is the best sales day and the mean and range are both 4

Note to teacher: Doing this activity once with a class helps students develop strategies. It is only when they do this activity a second time that they will have the opportunity to practise those strategies. That is when the learning is consolidated. Click the button above to regenerate another version of this starter from random numbers.

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 Teacher, do your students have access to computers?Do they have iPads or Laptops in Lessons? Whether your students each have a TabletPC, a Surface or a Mac, this activity lends itself to eLearning (Engaged Learning).

Transum.org/go/?Start=September12

Here is the URL which will take them to a related student activity.

Transum.org/go/?to=averages

For Students:

For All: