22 subjects are randomly injected with different dosages of insulin (X) and reduction rate in their blood-sugar levels (Y) are recorded. The results are summarized as:
ΣX = 132; ΣX2 = 917; ΣY = 44; ΣY2 = 348; ΣXY = 414; n=22
What is the estimate value for the average reduction rate in blood-sugar levels with increasing per unit of insulin dosage?