312-sample midterm4 and soln

Probability and Statistics for Engineering and the Sciences (with CD-ROM and InfoTrac )

This preview shows pages 1–2. Sign up to view the full content.

Stat312: Midterm Exam II. Moo K. Chung, Yulin Zhang November 11, 2004 Please use the following R output in answering the appropriate exam problems. > pnorm(c(1.0,1.1,1.2,1.3,1.4,1.5,1.6)) [1] 0.84 0.86 0.88 0.90 0.92 0.93 0.95 > pt(c(1.0,1.1,1.2,1.3,1.4,1.5,1.6),9) [1] 0.83 0.85 0.87 0.89 0.90 0.92 0.93 > pt(c(1.0,1.1,1.2,1.3,1.4,1.5,1.6),10) [1] 0.83 0.85 0.87 0.89 0.90 0.92 0.93 1. A mixture of pulverized fuel ash and Portland ce- ment should have a compressive strength of more than 1000KN/m 3 . The mixture will not be used unless experimental evidence indicates that the strength specification has been met. Suppose com- pressive strength for specimens of this mixture is normally distributed with σ 2 = 98 2 . The sample mean of compressive strength for 10 specimens is ¯ x = 1050 . (1) What are the appropriate null and alternate hy- pothesis (5 points)? (2) What would be the appropriate test statistic for the hypothesis testing? What is the probability dis- tribution of your test statistic when H 0 is true? (5 points each) (3) Do hypothesis testing at 85% level. Has the strength specification been met (10 points)?

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern