How many jelly beans?

When using this task you need to pace it to slides 1-2 only, ask everyone to estimate and when everyone has completed it then open up the remaining slides for them to access. In this task students are asked to estimate the number of jelly beans in a jar. Then it is revealed that they have been put into one of two conditions: 1. Those with a table of previous lower 'guesses' 2. Those with a table of previous higher 'guesses' They are then asked to work out the mean, median, range and standard deviation of the estimations under both conditions and state whether they think the previous 'guesses' had an effect on people's estimates.

By Catherine van Saarloos