SOFA platelet calculation

[tariqdam]

In sofa.ipynb, the platelet score is calculated as follows:

#calculate SOFA coagulation score:
sofa_platelets.loc[:,'sofa_coagulation_score'] = 0
sofa_platelets.loc[(sofa_platelets['value'] < 150) & 
                     (sofa_platelets['value'] >= 100), 'sofa_coagulation_score'] = 1
sofa_platelets.loc[(sofa_platelets['value'] < 100) & 
                     (sofa_platelets['value'] >= 50), 'sofa_coagulation_score'] = 3
sofa_platelets.loc[(sofa_platelets['value'] < 50) & 
                     (sofa_platelets['value'] >= 20), 'sofa_coagulation_score'] = 3
sofa_platelets.loc[(sofa_platelets['value'] < 20), 'sofa_coagulation_score'] = 4

Platelet values between 50 and 100 are now awarded a value of 3, but shouldn't this be a value of 2?

[patrickthoral]

Of course! I'll fix this together with the incorrect gamma assignment of #63