T2/T1=0.43
T4/T2=0.74
T6/T3=0.75
T8/T4=0.75
learning percent is 75%

b) T1 is obviously discordant data. This is called the "Fubar effect"
 T1 should have been:
T2/T1=0.75
T1=T2/0.75= 190?0.75=253

c) 72/253=0.284
from the 75% table, this corresponds to about 21 lots

d) this should be an improvement after 21 lots and will eventually pay off if it continues to get better.
We can't tell for sure cause it hasn't been done yet, but it will only work if you make life easier for the people who are doing the work.