Is there a Correlation?
Question 1: Abundance and Light
A student wanted to know how the abundance of daisies changed between open grassland and
woodland.
She placed a rope running from a grassy field into a wood.
At each of the sites marked along the rope she measured the number of daisy plants enclosed in an
area of one metre squared.
Woodland
10
9
8
7
Grassland
6
5
4
3
2
1
Sample sites
Her results are recorded in the table below.
Sample site
No. of daisy plants per
metre squared
1
2
3
4
5
6
7
8
9
10
19
20
18
27
12
8
4
1
0
0
Is there a statistically significant relationship between location and abundance of the daisies? Use
Spearman’s Rank Correlation Coefficient (rs) in your analysis of the results
Question 2: Yeast and Temperature
A student set up an experiment as shown opposite.
The water bath was heated to 30⁰C, and the yeast left for
5 mins to allow the temperature of the yeast to equilibrate
with the temperature of the water bath.
The rate of respiration in the yeast was then measured by
recording the number of bubbles produced over 1 minute.
The experiment was then repeated at 40, 50, 60, 70, 80
and 90⁰C
The final results are shown below
Temperature (⁰C)
10
20
30
40
50
60
70
80
90
Rate of respiration (Bubbles
per minute)
2
5
9
17
32
12
4
0
0
What, if any, is the relationship between temperature and abundance of the daisies? Use Spearman’s Rank
Correlation Coefficient (rs) in your analysis of the results
GHB 2011