In Fig. 5 the pattern changes at the higher values of parity.
Table 2 shows how Spearman’s and Pearson’s correlation
coefficients change when seven patients having higher
values of parity have been excluded. When the seven higher
parity values are excluded, Pearson’s correlation coefficient
changes substantially compared to Spearman’s correlation
coefficient. Although the difference in the Pearson Correlation
coefficient before and after excluding outliers is not
statistically significant, the interpretation may be different.
The correlation coefficient of 0.2 before excluding outliers
is considered as negligible correlation while 0.3 after excluding
outliers may be interpreted as weak positive correlation
(Table 1). The interpretation for the Spearman’s correlation
remains the same before and after excluding outliers with a
correlation coefficient of 0.3.The difference in the change
between Spearman’s and Pearson’s coefficients when outliers
are excluded raises an important point in choosing the
appropriate statistic. Non-normally distributed data may
include outlier values that necessitate usage of Spearman’s
correlation coefficient.