Answer and steps to question 21 20) The DBHs (Diameters at Breast Height) of the

Question

Answer and steps to question 21

20) The DBHs (Diameters at Breast Height) of the Interior trees in Question 19 (Douglas-firs and Hemlocks taken together) are normally distributed with an average of 20 cm and a standard deviation of 5 cm. What is the probability that the researcher will select a tree that a) ...less than 15 cm in diameter? b) .between 15 and 20 cm in diameter? c) .. .greater than 20 cm in diameter? d) ...less than 15 cm or greater than 20 cm in diameter? 21) The researcher is working for a forest products company that wishes to buy the biggest 45% of the Douglas-firs and Hemlocks from an Interior cut block. Based on the information in Question 20, what is the minimum diameter that the company should set its debarkers at?

Explanation / Answer

mean is 20 and standard deviation is 5

for biggest 45% we need to look at the value from the left of the curve till 1-0.45 i.e 55% from the left.. This gives a z value of 0.13. Thus, answer is 20+0.13*5=20.65

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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