Measuring the distribution of organisms

This activity is designed to show students how random sampling can be used to determine a true distribution of organisms within a given area.
Sheet 1 contains a 6 x 6 grid populated at random by 3 different types of organism. (print as A3 one per work group)
You will need two dice.
Throw both dice.
The number on the first dice tells you the column number you should sample.
The number of the second dice tells you the row number you should sample.
Count the number of each organism in the square and record these in your table.
Repeat this 11 times until your table is complete
Sheet 2 contains a work sheet to support students as they calculate mean, median, mode and state the range. (printed one per student A4 or A5)
(Any constructive feedback gratefully received)