Discussion in Aerospace Med » aerospace supplier

5 quick math stats question help just to be sure?

admin — Mon, 12 Oct 2009 03:46:08 +0000

1. A national organization has been working with utilities throughout the nation to find sites for large wind machines that generate electricity. Wind speeds must average more than20 miles per hour
(mph) for a site to be acceptable. Recently, the organization conducted wind speed tests at a particular site. To determine whether the site meets the organization’s requirements, consider the
test,H0:µ=20 vs.Ha:µ>20, whereµ is the true mean wind speed at the site and alpha=.01. Suppose the observed significance level (p-value) of the test is calculated to be p=0.4418. Interpret this result.

A)We are 55.82% confident thatµ=20.
B)Since the p-value greatly exceeds alpha=.01, there is strong evidence to reject the null hypothesis.
C)The probability of rejecting the null hypothesis is 0.4418.
D)Since thep-value exceeds alpha=.01, there is insufficient evidence to reject the null hypothesis.

2.If a hypothesis test were conducted using alpha=0.10, to which of the following p-values would cause the null hypothesis to be rejected.

A) 0.110
B) 0.105
C) 0.150
D) 0.090

3.A local eat-in pizza restaurant wants to investigate the possibility of starting to deliver pizzas. The owner of the store has determined that home delivery will be successful only if the average time spent on a delivery does not exceed 38 minutes. The owner has randomly selected15 customers and delivered pizzas to their homes in order to test whether the mean delivery time actually exceeds38 minutes. Suppose thep-value for the test was found to be .0274. State the correct conclusion.

A)At alpha= .02, we rejectH0.
B)At alpha= .05, we fail to rejectH0.
C)At alpha= .025, we fail to rejectH0.
D)At alpha= .03, we fail to rejectH0.

4.An industrial supplier has shipped a truckload of teflon lubricant cartridges to an aerospace customer. The customer has been assured that the mean weight of these cartridges is in excess of the 12 ounces printed on each cartridge. To check this claim, a sample of n=21 cartridges are randomly selected from the shipment and carefully weighed. Summary statistics for the sample are:x=12.17 ounces,s= .21 ounce. To determine whether the supplier’s claim is true, consider the test,H0:µ=12 vs.Ha:µ>12, whereµ is the true mean weight of the cartridges. Calculate the value of the test statistic.

A) 0.810
B) 17.000
C) 3.710
D) 1.700

5.The business college computing center wants to determine the proportion of business students who have laptop computers. If the proportion differs from30%, then the lab will modify a proposed enlargement of its facilities. Suppose a hypothesis test is conducted and the test statistic is 2.5. Find the p-value for a two-tailed test of hypothesis.

A) .4876
B) .0124
C) .4938
D) .0062

I just want an input to what you guys know and if you can explain it, it would be nice as well. I’m not confident if I did those problems right. Thanks a lot math geeks.

1. D
The answer basically explains itself. When the p-value is greater than the alpha-value, you can’t reject Ho

2. D
Again, to reject Ho, the p-value must be less than alpha. Since alpha is .1, choice D is the only p-value less than alpha

3. C
Same concept. If palpha, we fail to reject

4. C
First you need to find the standard error, which is equal to the square root of (s^2/n) = square root of (.21^2/21) = .046. This acts as the standard deviation of the sampling distribution. The mean of the sampling distribution is equal to Ho which is 12. The test statistic (or t) equals (x-µ)/SE = (12.17 – 12)/.046 = 3.71.

5. B
I didn’t fully understand this one, but if the test statistic is 2.5, then the p-value is 2 x normalcdf(2.5,1000) = .124

By the way, how do you type µ on the keyboard?

Looking for an aluminum / stainless steel metal cleaning alternative to lacquer thinner?

admin — Tue, 06 Oct 2009 14:08:03 +0000

Currently my company is using 55 gallon drums of lacquer thinner to clean grime, dirt, ink, etc. off of aerospace parts made of aluminum, stainless steel, and steel. As we know the lacquer is a hazardous substance which emits much vapor. What (safer) alternatives are available? Supplier phone numbers? I see dow has chlorinated solvents available in Europe, any dealer information would be helpful on those as well. We are located in MI. Thx.

Contact trade associations or to get offers from suppliers and manufacturers of metal cleaners, send an email with your requirement to buy@epog.org

Lec 13 | Special Topics in Supply Chain Management

admin — Tue, 15 Sep 2009 17:31:48 +0000

RFID R and D Opportunities and the Supply Chain (cont.)

Dick Cantwell, P and G / Gillette
Claus Garbisch, DHL Solutions
Brian Subirana, MIT

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Duration : 1:23:44

[youtube pqdN-zGWkfY]

Need help on a difficult Math question.?

admin — Mon, 14 Sep 2009 03:34:54 +0000

An industrial supplier has shipped a truckload of teflon lubricant cartridges to an aerospace customer. The customer has been assured that the mean weight of these cartridges is in excess of the 14 ounces printed on each cartridge. To check this claim, a sample of n=25 cartridges are randomly selected from the shipment and carefully weighed. Summary statistics for the sample are: x= 14.14 ounces, s = .25 ounce. To determine whether the supplier’s claim is true, consider the test, Ho: p<14 vs Ha: p>14 where p is the true mean weight of the cartridges. Calculate the value of the test statistic and the rejection region. Use α=.025

I keep gettin – (Test Stat 1.4 Rejection Region: z > 2.064)

I get t = 2.8 (when you only have the sample standard deviation you use a t-test; you can only use the z-test when you have the population standard deviation). This has a p-value of .004, which means you can reject at a=.025.

The rejection region is t>2.064 by saying the rejection area is .025 and there are 24 degrees of freedom.

Lec 9 | Special Topics in Supply Chain Management

admin — Sat, 12 Sep 2009 18:36:58 +0000

Healthcare and Life Sciences Requirements for RFID

Michael Rose, Johnson and Johnson
Robert Celeste, EPCglobal
Thomas Pizzuto, Wyeth Pharmaceuticals
Ted Ng, McKesson

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Duration : 0:46:4

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Where can i find/buy old scrap 737 aircraft seating?

admin — Sat, 12 Sep 2009 01:15:25 +0000

I would like to purchase or loan it from any aerospace company globally for my school. Its for a school project and for educational purposes. Are there any such suppliers globally?

There are bone yards all over the place. I would suggest that you pick up a Trade-a-Plane, its a classified for everything aircraft.

Lec 5 | Special Topics in Supply Chain Management

admin — Wed, 09 Sep 2009 16:39:31 +0000

R and D Opportunities and the Future of RFID Frequencies

Peter Cole, University of Adelaide
Alan Levesque, WPI
Leena Ukkonen and Lauri Sydanheimo, Tampere University of Technology
Richard Fletcher, MIT

View the complete course at: http://ocw.mit.edu/ESD-290S05

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Duration : 1:2:43

[youtube IXddoba3uQ4]

Lec 7 | Special Topics in Supply Chain Management

admin — Sun, 06 Sep 2009 18:14:32 +0000

Aero-Astro Technology and Research – Active RFID Standardization Pathway

Alan Thorne, Cambridge University
Ken Porad, Boeing

View the complete course at: http://ocw.mit.edu/ESD-290S05

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Duration : 0:42:25

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L-3 Communications

admin — Thu, 03 Sep 2009 19:17:31 +0000

L-3 Communications Corporation is a leading supplier of a broad range of products and services used in a substantial number of aerospace and defense platforms. We are also a major supplier of systems, subsystems and products on many platforms, including those for secure networked communications and communication products, mobile satellite communications, information security systems, shipboard communications, naval power systems, missiles and munitions, telemetry and instrumentation and airport security systems. We also are a prime system contractor for aircraft modernization and operations & maintenance (O&M), Command, Control & Communications (C3), Intelligence, Surveillance and Reconnaissance (ISR) collection systems and services, training and simulation, intelligence services and government support services. Our customers include the U.S. Department of Defense (DoD) and its prime contractors, the U.S. Department of Homeland Security (DHS), U.S. Government intelligence agencies, major aerospace and defense contractors, allied foreign government ministries of defense, commercial customers and certain other U.S. federal, state and local government agencies.

Duration : 0:1:30

[youtube unkEpEUxDCo]

Lec 15 | Special Topics in Supply Chain Management

admin — Mon, 31 Aug 2009 20:11:47 +0000

RFID Systems and Applications Beyond the Supply Chain

Steve Miles, MIT (Moderator)
Zhiwen Zhang, Ministry of Science and Technology, China
Peter Friess, European Commission
Daeyoung Kim, ICU
Jin Hee Yoon, SK Telecom

View the complete course at: http://ocw.mit.edu/ESD-290S05

License: Creative Commons BY-NC-SA
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More courses at http://ocw.mit.edu

Duration : 1:6:42

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