An engineer who is studying the tensile strength of a steel alloy intended for use in golf club shafts knows that tensile strength is approximately normally distributed with . A random sample of 12 specimens has a mean tensile strength of . (a) If the mean strength is 3500 psi, what is the smallest level of significance at which you would be willing to reject the null hypothesis

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x

8.75

how-to:

first, we need to find what we have to work with.

since i know that we have 7 (years) and 0.8 (inches), we can use these to solve and find the equation!

secondly, what you want to do, is see that we need to know how much growth out of the 0.8 inches he got in only 1 year, instead of 7 years.

let's try to divide.

7 ÷ 0.8 = 8.75