Bird species from temperate regions must cope with relatively short breeding seasons. A study examined the relationship between blood testosterone level (ng/ml) and the duration of the egg-laying period (months) in temperate bird species. The scatterplot below displays this relationship, after taking the logarithm of each variable. A plausible value for the correlation between the logarithm of egg-laying duration and the logarithm of testosterone level is
In that situation, the value of the possible correlations between the egg-laying logarithm as well as the testosterone level logarithm is equal to 4 It value is equal to the percentage 4=-0.4.
