use loops to tidy up code with respect to summaries for all PA metrics selected
use loops to tidy up code with respect to summaries for all PA metrics selected

aidendoherty/biobankAccelerometerAnalysis,computationalEpidemiology/biobankAccelerometerAnalysis,computationalEpidemiology/biobankAccelerometerAnalysis,aidendoherty/biobankAccelerometerAnalysis