Answer:
a. We fail reject to the null hypothesis because zo = -5.84 < 1.65 = zα and P-value = 1 (approximately)
b. The confidence Interval for u1 - u2 is; 6.79 ≤ u1 - u2
c. The power of the test = 1 -
β = 0.998736
d. The sample size is adequate because the power of the test is approximately 1
Step-by-step explanation:
Given
Standard Deviations; σ1 = σ2 = 1.0 psi
Size: n1 = 10; n2 = 12
X = 162.5; Y = 155.0
Let X1, X2....Xn be a random sample from Population 1
Let Y1, Y2....Yn be a random sample from Population 2
We assume that both population are normal and the two are independent.
Therefore, the test statistic
Z = (X - Y - (u1 - u2))/√(σ1²/n1 + σ2²/n2)
See attachment for explanation
One approach that might be a great help would be if you would look
at the choices ... those things at the bottom of the question that you
didn't give us.
-- One leg is 3 times the length of the other leg.
-- Any right triangle that has one leg three times as long as the other
leg is similar to this triangle.
I'll bet that if you look through the choices, you'll find one there.
That is not correct. I will help you. Begin by subtracting the 9x from both sides, like this: 9x - 9x + 2y = 6 - 9x. That simplifies to 2y = -9x + 6. Now divide both sides by 2 to get y all alone, like this:

. That reduces down to

. That is slope-intercept form. y = mx + b.
3x - 7 + 7 = 12 + 7
3x = 19
3x/3 = 19/3
X = 19/3 = 6 1/3