Testing Definition and 589 Threads

As far as I can tell for the equation n!/n^2=x or n-1!/n=x, if x is a natural number then it seems n is composite. If x is a non-natural number then it is prime (excluding 4). I am aware that this is not very practical since I am using factorials and the numbers get very large. But it still...

Let us define a relation a on the set of nonnegative real triples as follows: (a1, a2, a3) α (b1, b2, b3) if two out of the three following inequalities a1 > b1, a2 > b2, a3 > b3 are satisfied. a) (3) Test a for Transitivity and Antisymmetry We call a triple (x, y, z) special if x, y, z...

Chasing a ghost perhaps but in the process of pressure testing a simple propane furnace installation I installed a water Column pressure gauge. Over a period of 11 hours the pressure gauge reading will go from 10" WC to 0" WC. In the course of trying to understand this I installed a manometer...

Hi all, I am doing a High Velocity Impact testing using a gas gun I have to figure out a) is my test running well and I am not getting any reflection? Please correct me or help in calculating if I am wrong at any point. I guess, I can figure out by calculating the time required for the...

Hi, I’m new here and come to ask you for some help. I would like to ask you to give me a few examples of automated sample extraction from laboratory oven for mechanical properties testing. It could be in form of scientific articles, videos or anything else, where something like that might be...

< Mentor Note -- thread moved to HH from the technical forums, so no HH Template is shown >[/color] experiment for testing type of catalyst on reaction rate? I need an experiment (just the method) Where I can test the reaction rate of changing the catalyst type I need about 3 differnet...

In Megger testing distribution transformers, how much importance is there in including the LV/HV bushings in the test. If you disconnect and have high readings independant of the bushing, and then put the bushings back into the circuit and the readings fall dramatically, what is that saying...

Hello, I would like to develop a testing method to detect window defroster grid failures. Rear windows has 12 heating wires painted to the glass and cca. 2% are faulty pieces. I tried to measure the resistance, current and voltage drop of good parts and compare results with those where was at...

Hey, I am a second year university student in BioMedical-Engineering and I've been looking to try something new. DIY is something I have been into for a while, I own and operate a 3d printer and I'm building other projects. So complexity is not really an issue as long as there is information...

I'd like to learn how to test for these types of cells (living or dead) in water. what do I need to do this from home ? is it cheap or expensive to buy the equipment ? please provide details of the equipment needed and just a rough idea as to the cost of doing so at home. oh yeah once i buy the...

Homework Statement http://prntscr.com/8ea2rk Homework Equations In statistics, when testing hypothesis for both sides (left and right), is it possible that Xaverage - MUo = 0 (upper part of the equation I provided)? If so how to solve this kind of task? The Attempt at a Solution If I get...

So (this is my first thread by the way so sorry if it is in the wrong place) I am now a junior who has just started junior year (Last week). I am taking AP Physics C and AP Calc BC concurrently. I have always been pretty good at math and physics, but never amazing, just around mid to low A...

As an amateur, I am just testing my understanding on the following, since there is nothing worse than harbouring misconceptions. Suppose we have a space-time ( e.g. of FRW type ) which is conformally flat : C{^{\mu \nu }}_{\rho \sigma }=0 but not Ricci flat : R_{\mu \nu }\neq 0 Would that...

Just wondering if anyone happened to know how to find out the policy at University of Indianapolis for taking something like calculus or statistics. It just seems like a work load if they have you tests by hand. I'd just like to know because it'd make me relieved.

Hello. I have no experience as a cellular biologist nor have any lab experience or knowledge. However I would like to know how would one go about finding out what is needed in order to test the following foods mostly for human cells (any kind) : 1. How can I examine the following food items...

Hello everyone, I'm in the process of building a flow bench to test cylinder heads. What I'm after is to make a pitot tube to measure port velocity. Any help would be appreciated. Thanks

I am looking forward to joining discussions here. My Backgroud is 2 years "applied physics", 5 years education for teaching in visual communication (art), 15 years experience as a database software developer. Now I am looking for a job as a software tester. Software Testing is similar to being...

Homework Statement "Determine whether the following series converge or diverge. If the series is geometric or telescoping, find its sum.": ## \left ( \sum_{k=1}^\infty2^{3k} *3^{1-2k} \right)## Homework Equations [/B] The different tests for convergence? The Attempt at a Solution Ok...

Hello, I'm hoping someone can give me some insight to my fears. To start, I cheated on my long term boyfriend #1 (whom I'll reference as #1 going forward) with my ex-boyfriend #2(referenced as boyfriend #2) within a 30 hour period. Boyfriend #1 and I don't practice safe sex. Boyfriend #2 and I...

I am a part C Mechanical Engineering student and have been undertaking a project investigating the strain sensitivity of a particular glass filled composite. From my quasi-static results, the stress-strain curves seem to be reasonable and match that of the mechanical material properties...

I am a part C mechanical engineering student and require some advice for my individual project, which is based on the high strain-rate testing of a particular glass filled composite material using a split-Hopkinson pressure bar (SHPB) experiment. I gathered the results on a SHPB test rig and...

Hello.I need help with wind tunnel.The test section is 2m x 2.5 m x 5 m long.How do I work out size of inlet cone.Thanks in advance

So I am only a sophomore but I feel that i have my mind set on going to college and embarking on a phd in physics. As of now I seem to go by school quite easily with a 4.0 and I don't even study (I go to a pretty nice private school) . Not like that's something I should really be bragging about...

Hello, has anyone here had anxiety issues when taking tests before and noticed a difference in performance after taking medication? I have pretty bad anxiety before my exams, and find myself making very little mistakes that still show I understand the material. For example, when asked to...

Hey all, I have been put in charge of developing my company's research and development "lab" and I am currently looking for some testing equipment to buy. My background is in civil engineering, however I did do a small amount of material testing in school, and I'm familiar with the concepts...

Homework Statement How does the RC-link help with adding ripple to the signal? What would happen if the capacitor was removed (short-circuited)? Homework EquationsThe Attempt at a Solution I believe that the role of the capacitor is to pass on the AC voltage. Initially the capacitor is charged...

Homework Statement The attachment depicts an active load (to the right is the equivalent circuit). It is called thus because this load (measured from TP27) changes its resistance according to the controlling signal connected to TP25. The load is switched “on” (minimum resistance) and “off”...

Homework Statement The life in hours of a battery is known to be normally distributed, with standard deviation of 1.5 hours. A random sample of 12 batteries has a sample mean life time of 50 hours. a) Test the hypothesis that the mean battery life is 50.5 hours (by using α = 0.05). b) What is...

Hello guys, I have a sample of about 400 natural numbers though I can get more numbers. To give you an idea the mean and the standard deviation are 29038031 and 1842882 respectively and I expect the numbers to follow a Gaussian distribution. I'd like to perform a test to tell me the probability...

Homework Statement State the null and alternative hypotheses. The decision to implement changes in the current math program at a junior high will be based on a sample of students' scores on a standardized math exam. If the average is less than the statewide average of 89, all math teachers...

Hello all, I'm going into my senior year of applied mathematics this coming Fall semester. My adviser recommended that I take the GRE before Fall semester starts so that I can have my Grad school applications in by the December deadline. My question is as follows: Would it be better to study...

Hi, Excuse the ignorance of an electronic engineer here but is there a procedure/tool to measure for leaks in pneumatic cylinders? One that will give a percise reading, ie. 30% pressure loss in a cylinder. This is not an automobile qusetion and not a combustible engine leak down test just a...

Any recommendations for getting an accurate reading of a magnetic field in a solenoid coil? They're ferrite cores wrapped with magnetic copper wire. Would putting a Hall sensor at the end of the ferrite be a reasonable way to do this? Or will the field have already diverged? (The coil stops...

Hello I'm currently in high school but I am teaching myself ALOT of math and physics. I'm planning to go to Princeton, MIT, or Stanford. I am curious, since I will already know all of it, if I will be able to acquire a Bachelors degree in physics in one or two years by testing out. If I do...

Is the ESD standard different for components(ICs) and systems. For Systems the standard I refer is IEC61000-4-2. For ICs, I am not sure. Does HBM and CDM apply to only components or does it apply to systems too? Is the Automotive ESD testing levels different than the industrial ones( 4KV...

Hi guys. I'm not a statistician although I use it enough that I'm surprised something is bothering me. I'm doing hypothesis testing on a population >100,000. What I'm wondering is whether there is any difference whatsoever between performing multiple tests on several samples or just doing one...

An optical low pass filter is supposed to blur the image using birefringence. I took out an optical low pass filter from a digital camera where it is used for anti-aliasing purposes. The filter looks just like a piece of glass. I pass a diode laser beam through it and look at the beam spot on...

Hi I'm not having a huge problem, but it bothers me. Today I noticed the indicator led in my power button doesn't work. I'm using an Acer 7750G laptop not entirely sure how old (funny how quick we forget and get used to such things). Is there any software method of testing this LED? I'm using...

Hello all. I was wondering if there is a method or a device to check the quality of the twists on twisted pairs cable harness vis-a-vis EMI. i.e. someway (to tell is the twists are good enough to pass EMI testing). Cheers

Hi all, I've a question and I hope that I can get some answers here. As what my project has tasked, and what my lecturer had said. He needs me to build a device for NDT Testing. Currently the set up is that I would source for a transducer via olympus coupled with a USB oscilloscope capable...

I am working on a system that uses capacitance sensor probes, the system components are the probe, triaxial cable with LEMO connectors, BNC cable, oscillator, and a demodulator. I have had some trouble finding ways to troubleshoot the system other then basically testing continuity. Are there any...

For my senior design project, I have to reduce the aerodynamic drag of a truck and trailer. I am doing CFD simulations and wind tunnel testing. The dimensions of the wind tunnel (test section) are 94 in long, 13.5 in tall and 20 in wide and a cross-sectional area of 270 in^2 and it could go up...

Hi all. This is my first question on these forums. I am given a task to test out whether or not FD=1/2 CDAρv2 is a good model to test drag force. Where CD is described by Reynold's Number. We have a balloon a small ball and a myriad of basic physics lab equipment.What is a experiment I could...

Homework Statement Suppose a mutual fund qualifies as having moderate risk if the standard deviation of its monthly rate of return is less than 6%. A mutual-fund rating agency randomly selects 28 months and determines the rate of return for a certain fund. The standard deviation of the rate of...

Hello. The university I attend allows you to challenge some courses for grad school. Two of them are Real Analysis I and Real Analysis II. This made me consider trying it. The cost of the challenge test is the same as the cost if you took the course so it really has to count. I wanted to...

Hi, I am new to the tensile testing and still learning and would really appreciate the answer to a problem that I have been having. I performed a lap-shear test on two foils of copper bonded in single lap joint. The copper broke before the bond does giving me a force of say 500N. I want to...

My question is on how to answer if two statements are equal in set theory. Like De'Morgans laws for example. I'm currently reading James Munkres' book "Topology" and am working through the set theory chapters now, and this isn't the first time I've seen the material, but every time I see this...

The problem: A simple random sample of 1862 births of Chinese babies resulted in a mean birth weight of 3171 g and a standard deviation of 428 g (based on “Comparison of Birth Weight Distributions between Chinese and Caucasian Infants,” by Wen et al., American Journal of Epidemiology, Vol.172...

Hi everyone. It's been years since I've done any stats, so I need a bit of help, please. I want to include it in a blog post I'm going to do (not here on PF), so I don't want to give away too many details :p I apologise for my terrible understanding of stats, please be patient! Anyway, over...

Homework Statement Hello Everyone! I am having trouble with one of my questions it goes: It is claimed that fewer than 30% of Thunder Bay households have home delivery of the newspaper. To test this claim, a random sample of 390 Thunder Bay households reveals that only 95 get the paper...