OD
(Choose 1 answer)
(See picture)
A. None of the others
B. The new ingredient significantly reduces the mean drying time.
C. The new ingredient significantly increases the mean drying time.
D. The new ingredient does not change the mean drying time.
A product developer is interested in reducing the drying time of primer paint.Two formulations of the paint are tested; formulation 1 is the standard chemistry,and formulation 2 has a new drying ingredient that should reduce the drying time. From experience, it is known that the standard deviation of drying time is 8 minutes, and this inherent variability should be unaffected by the addition of the new ingredient.
Ten specimens are painted with formulation 1, and another 10 specimens are painted with formulation 2; the 20 specimens are painted in random order.
Two sample average drying times (minutes) are x₁ = 121; x2 = 112.
What conclusions can the product developer draw about the effectiveness of the new ingredient, using a = 0.05? Given that Z0.025 1.96; Z0.05-1.645
