"pre.test" "post.test"
"1" 30 29
"2" 28 30
"3" 31 32
"4" 26 30
"5" 20 16
"6" 30 25
"7" 34 31
"8" 15 18
"9" 28 33
"10" 20 25
"11" 30 32
"12" 29 28
"13" 31 34
"14" 29 32
"15" 34 32
"16" 20 27
"17" 26 38
"18" 25 39
"19" 31 32
"20" 29 32