Review A-Level Edexcel Biology dispersion, standard deviation and range through the available evidence on mean-and-range calculations in inhibition-zone data.
Soil contains many types of organisms such as earthworms.
A scientist investigated the mass of earthworms present in the soil of a 5-year-old plantation and a 15-year-old plantation. The method used in each plantation was: - five sample sites were selected at random - a block of soil with an area of and to a depth of 10 cm was removed at each site - the total mass of earthworms present in each block of soil was recorded.
The tables show the results of this investigation.
Calculate the standard deviation for the mass of earthworms present in the soil of the 15-year-old plantation. Use the formula:
Where: n is the number of sample sites X is the mass of earthworms from one sample site is the mean mass of earthworms
Describe how the means and standard deviations could be used to compare the results from these two plantations.