Standard DeviationFind how 'spread out' data is by estimating and calculating this measure of dispersion 
This is level 2: without a calculator find the standard deviation of a small data set. You can earn a trophy if you get at least 4 questions correct and you do this activity online.
InstructionsTry your best to answer the questions above. Type your answers into the boxes provided leaving no spaces. As you work through the exercise regularly click the "check" button. If you have any wrong answers, do your best to do corrections but if there is anything you don't understand, please ask your teacher for help. When you have got all of the questions correct you may want to print out this page and paste it into your exercise book. If you keep your work in an ePortfolio you could take a screen shot of your answers and paste that into your Maths file. 



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Mathematicians are not the people who find Maths easy; they are the people who enjoy how mystifying, puzzling and hard it is. Are you a mathematician? Comment recorded on the 19 June 'Starter of the Day' page by Nikki Jordan, Braunton School, Devon: "Excellent. Thank you very much for a fabulous set of starters. I use the 'weekenders' if the daily ones are not quite what I want. Brilliant and much appreciated." Comment recorded on the 14 September 'Starter of the Day' page by Trish Bailey, Kingstone School: "This is a great memory aid which could be used for formulae or key facts etc  in any subject area. The PICTURE is such an aid to remembering where each number or group of numbers is  my pupils love it! 


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Level 1  Compare small data sets by estimating their dispersion
Level 2  Without a calculator find the standard deviation of a small data set
Level 3  Use a calculator find the standard deviation of a data set
Level 4  Use a calculator find the standard deviation of grouped data
Exam Style Questions  A collection of problems in the style of GCSE or IB/Alevel exam paper questions (worked solutions are available for Transum subscribers).
More Statistics Resources including lesson Starters, visual aids, investigations and selfmarking exercises.
Answers to this exercise are available lower down this page when you are logged in to your Transum account. If you don’t yet have a Transum subscription one can be very quickly set up if you are a teacher, tutor or parent.
See the National Curriculum page for links to related online activities and resources.
This great video is from Jeremy Jones.
The objective of this exercise is to give you a small amount of practice calculating standard deviation using pen and paper just so that you get a 'feel' for the concept.
Example: find the standard deviation of the following values: {6,18,6,18}
Find the sum: 6 + 18 + 6 + 18 = 48
Find the mean: 48 ÷ 4 = 12
Find the difference between each number and the mean then square that difference. Add the squares:
(612)² + (1812)² + (612)² + (1812)²
= 36 + 36 + 36 + 36 = 144
Divide this by the number of items:
144 ÷ 4 = 36
This is the variance. Find the square root of the variance to give a standard deviation of 6.
Don't wait until you have finished the exercise before you click on the 'Check' button. Click it often as you work through the questions to see if you are answering them correctly. You can doubleclick the 'Check' button to make it float at the bottom of your screen.
Answers to this exercise are available lower down this page when you are logged in to your Transum account. If you don’t yet have a Transum subscription one can be very quickly set up if you are a teacher, tutor or parent.
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