A marine biologist is investigating the relationship between the depth $D$ (in metres) of a coral reef and the condition score $S\,$ of the coral (ranked from 1 to 7, where 7 is the most degraded and 1 is the most pristine). She suspects that coral located at greater depths is more prone to degradation. She collects data from 7 different sites, as shown in the table below:


Depth $D$ (m)	4.5	12.8	8.2	22.1	2.3	35.6	17.4
Condition Rank $S$	3	4	2	7	1	6	5

Calculate Spearman's rank correlation coefficient ( $r_s$ ) for these data.

Stating your hypotheses clearly and using a one-tailed test at the 5% level of significance, interpret your coefficient. (The critical value for $n = 7$ at the 5% level is 0.7143).

State a reason why Spearman's rank correlation coefficient might be more appropriate than the product moment correlation coefficient (PMCC) for this specific dataset.


Depth $D$ (m)	4.5	12.8	8.2	22.1	2.3	35.6	17.4
Condition Rank $S$	3	4	2	7	1	6	5

Calculate Spearman's rank correlation coefficient ( $r_s$ ) for these data.

Stating your hypotheses clearly and using a one-tailed test at the 5% level of significance, interpret your coefficient. (The critical value for $n = 7$ at the 5% level is 0.7143).

State a reason why Spearman's rank correlation coefficient might be more appropriate than the product moment correlation coefficient (PMCC) for this specific dataset.

4.3.1 Statistical hypothesis testing (A-level only)

Question 76

Markscheme

4.3.1 Statistical hypothesis testing (A-level only)

Question 76

Markscheme

4.3.1 Statistical hypothesis testing (A-level only)

Question 76

4.3.1 Statistical hypothesis testing (A-level only) Questions

4.3.1 Statistical hypothesis testing (A-level only)

Question 76

4.3.1 Statistical hypothesis testing (A-level only) Questions