# Hw2 - Engineering Statistics ENGRD270 Homework 2...

• Homework Help
• 2

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

Engineering Statistics ENGRD270 Homework 2: Descriptive Statistics (contd) Spring 2008 Hand in by 1pm on Fri, Feb 8 in the ENGRD270 dropbox (between 2nd floor Rhodes and 3rd floor Upson). Be sure to write your name and section number (1–6) or day&time on your homework. 1. The “handy” formula for the sample correlation coefficient. For a sample of pairs ( X 1 , Y 1 ) , . . . , ( X n , Y n ), show the alternate formula r = [ X X i Y i - n X · Y ] / [( n - 1) S X S Y ] . Here S 2 X = [ X 2 i - n X 2 ] / ( n - 1) and similarly S 2 Y . [ Hint: Study the “computing formula” for the sample variance in Devore 7e, page 34.] 2. In an experiment, two types of .45 caliber bullets (230 grain and 200 grain) were fired several times into oak wood from a distance of 15 feet. The penetration depths (in mm.) for each firing can be found the following table: 230 grain 40.5 38.3 56.0 42.5 38.3 27.8 200 grain 63.8 64.6 59.5 60.7 58.0 59.1 55.8 54.6 The first row represents the penetration depths of six firings of the 230 grain bullets and the second row of eight firings of the 200 grain bullets. In this question it is best if you can figure out how to use MINITAB to produce all the plots (or some other software). (The Help facility or the

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

This is the end of the preview. Sign up to access the rest of the document.
• Spring '05
• STAFF
• Big Bang, Redshift, Edwin Hubble, grain bullets, penetration depths

{[ 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