1913
The measurements were taken at the beginning of , and at , 6 and 12 months during the intervention , and the differences were compared by paired Student ' s t and chi ( 2 ) tests .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None