![Substitution Cipher](/sites/default/files/styles/medium/public/thumbnails/content-id-4957-icon.png?itok=9CmEuTVv)
problem
Substitution Cipher
Find the frequency distribution for ordinary English, and use it to help you crack the code.
![In the bag](/sites/default/files/styles/medium/public/thumbnails/content-id-6016-icon.jpg?itok=kXQEDWEf)
problem
In the bag
Can you guess the colours of the 10 marbles in the bag? Can you develop an effective strategy for reaching 1000 points in the least number of rounds?
![Reaction timer](/sites/default/files/styles/medium/public/thumbnails/content-id-6044-icon.png?itok=EGmCGgof)
problem
Reaction timer
This problem offers you two ways to test reactions - use them to investigate your ideas about speeds of reaction.
![m, m and m](/sites/default/files/styles/medium/public/thumbnails/content-id-6267-icon.png?itok=Q1S8r2JO)
problem
m, m and m
If you are given the mean, median and mode of five positive whole numbers, can you find the numbers?
![How would you score it?](/sites/default/files/styles/medium/public/thumbnails/content-id-6957-icon.png?itok=nYlVH8au)
![Olympic Records](/sites/default/files/styles/medium/public/thumbnails/content-id-7489-icon.jpg?itok=FVH5AjGC)
problem
Olympic Records
Can you deduce which Olympic athletics events are represented by the graphs?
![Statistical shorts](/sites/default/files/styles/medium/public/thumbnails/content-id-7721-icon.png?itok=cx7E2WA8)
problem
Statistical shorts
Can you decide whether these short statistical statements are always, sometimes or never true?
![About Average](/sites/default/files/styles/medium/public/thumbnails/content-id-10995-icon.png?itok=YMXj_aLy)
problem
About Average
Can you find sets of numbers which satisfy each of our mean, median, mode and range conditions?
![Half a minute](/sites/default/files/styles/medium/public/thumbnails/content-id-10999-icon.png?itok=_JHHaVAT)
![Searching for mean(ing)](/sites/default/files/styles/medium/public/thumbnails/content-id-6345-icon.png?itok=8iCcjK_N)
problem
Searching for mean(ing)
If you have a large supply of 3kg and 8kg weights, how many of each would you need for the average (mean) of the weights to be 6kg?
![Who's the best?](/sites/default/files/styles/medium/public/thumbnails/content-id-7367-icon.png?itok=-3MEzqSp)
![What's the weather like?](/sites/default/files/styles/medium/public/thumbnails/content-id-10470-icon.png?itok=WI00oRqQ)
problem
What's the weather like?
With access to weather station data, what interesting questions can you investigate?
![Estimating time](/sites/default/files/styles/medium/public/thumbnails/content-id-10629-icon.png?itok=4M7QcnJB)
![Wipeout](/sites/default/files/styles/medium/public/thumbnails/content-id-10996-icon.png?itok=j3fpxJ14)
problem
Wipeout
Can you do a little mathematical detective work to figure out which number has been wiped out?
![Unequal Averages](/sites/default/files/styles/medium/public/thumbnails/content-id-11281-icon.png?itok=L9ubz1Li)
problem
Unequal Averages
Play around with sets of five numbers and see what you can discover about different types of average...
![Litov's Mean Value Theorem](/sites/default/files/styles/medium/public/thumbnails/content-id-4838-icon.jpg?itok=b7a6Fnbo)
problem
Litov's Mean Value Theorem
Start with two numbers and generate a sequence where the next number is the mean of the last two numbers...
![Tree tops](/sites/default/files/styles/medium/public/thumbnails/content-03-06-six1-icon.jpg?itok=lB4lluZf)
problem
Tree tops
Can you make sense of information about trees in order to maximise the profits of a forestry company?
Image
![Statistics - Stage 3 STEM footer Statistics - Stage 3 STEM footer](/sites/default/files/styles/large/public/thumbnails/content-id-13478-STEMlogo.png?itok=jSmT_KQe)
You may also be interested in this collection of activities from the STEM Learning website, that complement the NRICH activities above.