Field Investigations
Q1.
Some students wanted to find the number of thistle plants growing on a lawn.
The students placed 10 quadrats at different positions on the lawn.
Each quadrat measured 1 metre × 1 metre.
The students counted the number of thistle plants in each quadrat.
(a)     Which method should the students use to decide where to place the 10 quadrats?
Tick () one box.
 
Place the quadrats as evenly as possible around the lawn.		
Place 5 quadrats in areas with many thistle plants and 5 quadrats in areas with only a few thistle plants.		
Place all the quadrats randomly on the lawn.		
(1)
(b)     The diagram shows the lawn with the positions of the thistle plants and the students’ 10 quadrats.
 
(i)      Complete the table to show:
•        how many thistle plants the students found in each of the first four quadrats
•        the total number of thistle plants found in all 10 quadrats.

	Quadrat
number	Number of thistle
plants in each
quadrat	
 
	1	 	
 
	2	 	
 
	3	 	
 
	4	 	
 
	5	1	
 
	6	3	
 
	7	0	
 
	8	0	
 
	9	2	
 
	10	1	
 
	Total	 	
(2)
(ii)     Calculate the mean number of thistle plants in one quadrat.
______________________________________________________________
Mean = ______________________________________________
(1)
(iii)    The lawn measured 12 metres long and 10 metres wide.
Use your answer from part (b)(ii) to estimate the number of thistle plants on the lawn.
______________________________________________________________
______________________________________________________________
Estimated number of thistle plants = _______________________
(2)
(c)     How could the students make their estimate more accurate?
___________________________________________________________________
___________________________________________________________________
(1)
(Total 7 marks)