a brick company found that 4% of its bricks were defective if400 bricks are chec

Question

a brick company found that 4% of its bricks were defective if400 bricks are checked at random what is the prob. that there aremore then 16 defective bricks a .2618 b.1859 c.1254 d.0486 e.0150 e none a brick company found that 4% of its bricks were defective if400 bricks are checked at random what is the prob. that there aremore then 16 defective bricks a .2618 b.1859 c.1254 d.0486 e.0150 e none

Explanation / Answer

This probability can be approximated using a normal approximation. That is because np = 400(0.04) = 16 >= 5 and n(1-p) = 400(0.96) = 384 >= 5. So, we will use a normal where mean = np = 16 and sd = sqrt{np(1-p)} = sqrt(400*0.04*0.96) = 3.92. Since we are using the normal, then we will have to make a correction on the 22. Since we want to find the proportion above 22, but not including 22, then we will want to start at 22.5 and shade to the right on our normal. So now this is just a normal, so find z. z = (22.5-16)/3.92 = 1.66 Using the standard normal table, you get the area to the right as 0.0485, so the answer is d.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.