Testing Definition and 589 Threads

Homework Statement Hi, I had a question regarding testing a regression models coefficients. Say there is a regression model that has the form: y = b0 + b1x1 + b2x2 + b3x3 + b4x4 + e For the sake of simplicity let: e be the random error, x1 is age, x2 is severity, and x3 is anxiety. y is...

Testing Quantum Gravity Johan Hansson, Stephane Francois (Submitted on 19 Oct 2017) The search for a theory of quantum gravity is the most fundamental problem in all of theoretical physics, but there are as yet no experimental results at all to guide this endeavor. What seems to be needed is a...

Homework Statement Given ##X_1,\dots,X_{100}##, test ##H_0: \lambda=1## against ##H_a: \lambda=4##. The mean ##\bar{X_{100}}=1.5## (1) Take the decision on 3% level. (2) Find the p-value Homework Equations ##t=\frac{\bar{x}-\mu}{s/\sqrt{n}}## The Attempt at a Solution The level of...

Hello! (Wave) I have read the proof that primality testing is in NP and I have a question about it. The proof is the following:Note that the group $(\mathbb{Z}/ N \mathbb{Z})^{\ast}$ is of order $N-1$ iff $N$ is prime. And more over, it is a cyclic group of order $N-1$ iff $N$ is a prime...

∑ (-2)n+1/n+5n Test this series Absolute Convergence ? ∑|an| = ∑(2)n+1/n+5n if the sum of |an| converges, than the sum of an converges ∑|an| = ∑(2)n+1/n+5n I can use Comparison Test? I can choose series bn = ∑ 2n/5n ?

[SIZE=16px][FONT=Helvetica Neue]Hi, when it comes to Transformer Oil testing, there are some parameters that we need to consider but i don't understand their definitions and i can't find their explanations online, so may someone please define these terms for me that what these terms actually...

String theory and M-theory and Kaluza Klein theories predicts additional extra dimensions at least 2 recent papers proposed tests these predictions of extra dimensions String theory phenomenology and quantum many body systems Sergio Gutiérrez, Abel Camacho, Héctor Hernández (Submitted on 24...

Hi All, I am trying to wrap my brain around Latent Class Analysis (LCA). In the mean time, does anyone know how to test for goodness of fit and whether a given number of classes is somehow optimal? AFAIK, Log-Likelihood should decrease as a measure of improved fit when adding latent classes...

Take for example 377 to test its primality. I will only test its divisibility with (3*5*7*...*125) (because 377/3=125.67, so here the multiplication series end with 125 ). 377 will be able to divide it. (Since I know 377=13*29, i.e in the numerator 13 & 29 will be divided by 377, hence...

I’m having some remodel work done on a couple rooms in my house. They will be adding a new CAT7 run and replacing the old coax (at least 20 years old). Is there any sort of “hack” I can do to test the speed of the new cables? The only thing I can think of is just moving my laptop around...

Homework Statement A crime has been committed and the police have only captured a suspect, although he obviously claims to be innocent. To give a verdict the judge authorizes the use of the lie detector. The manufacturer of the device warns the authority that the lie detector in 10% of the...

Ok, so in a logistic regression context, I need to test if the probability of ##Y_{i}=1 ## is the same for two different groups at different ages where age is a continuous variable. This is actually complicated because of nonlinearity. Can I default to testing if the odds of ##Y_{i}=1 ## is...

I get given a lot of brush-motor tools that are "burning', as well as assorted other damaged electrical items. I'm not an electrical engineer, just a fiddler with some background in physics. Now, Jim Hardy and Tom.G have just walked me through testing a 12V alternator, which was found, as far...

Pretty neat. Lowe's is equiping some employees with these exoskeletons to help them lift in their jobs with less overall strain on their backs. Virginia Tech is working with Lowe's on the design and testing of the exoskeleton "uniforms". :smile...

This paper; https://arxiv.org/abs/1704.08613, Entropy evolution of moving mirrors and the information loss problem, discusses a proposed method to test the information loss paradox posed by black hole evaporation. Several possible outcomes are discussed, including a firewall scenario...

I'm required to test a harizontal axis turbine's performance and plot a RPM vs Power curve. The turbine is driving a small DC generator that produces 5V at the turbine's maximum RPM with no other load on the generator. I am planning on installing different sized resistors in parallel with the...

As I understand it, there are two main types of ABS sensor - variable reluctance, two-wire and Hall effect, three-wire. The sensor I wish to test is the former. My meter has a frequency and duty cycle button, but which range should I use - AC or DC? I plan to test at the sensor plug while...

One of my longer posts. Please stay with me! Background: So as some of you know, for personal and financial reasons I had to leave school a bit early to get work and support my family. I was *almost* done anyway. I need only the qualifier for my master's (in pure math) and I was only taking...

I'm trying to solve https://www.hackerrank.com/challenges/equal which is how to make an array's N elements equal through operations restricted to (1) adding 1 to N-1 elements, (2) adding 2 to N-1 elements or (3) Adding 5 to N-1 elements. I started out by writing some test cases that might be...

This is not exactly engineering. Please move where appropriate if it's not. I am testing some 4G netcomm wireless routers to see how much traffic they can handle in certain situations. We are trying to find ways to "impede" them. They have two antennae that can be unscrewed. Removing both...

Not sure if this is the best place to ask this question but forums on this seem to be limited, can anybody explain how one would discover if a steel pole lighting structure is being effected by harmonic resonance? I do not know what tools and methods would be used, if anyone can provide some...

Use the following information to answer the questions below: A 0.01 significance level is used for a hypothesis test of the claim that when parents use the XSORT method of gender selection, the proportion of baby girls is different than 0.5. Assume that sample data consist of 62 girls born in...

Hi! I would like to submit a model glider to a CFD wind tunnel so I can determine what would be its optimum glide ratio and forward speed at this incidence. I am not supposed to know in advance the range of speed this glider can fly (between stall and structural damage), so the speed I will...

Homework Statement Consider the binary structure given by multiplication mod 20 on {4, 8, 12, 16}. Is this a group? If not, why not? Homework EquationsThe Attempt at a Solution I started by constructing a Cayley table, and working things out. It turns out that 16 acts as an identity element, 4...

Homework Statement During class we did a lab testing Le Chatelier's Principle where we took FeSCN-(aq) and added water in order to dilute it to a lighter colour (red to orange) and to make a stock solution. We then divided the stock solution into several test tubes. In one of them we added...

I'd like to test the quality and performance of an electrical item I intend to sell. I was able to find a similar, very high quality product whose quality I'd like analyzed and compared to lower quality alternative. Who should I send these two product samples to? A third party inspection...

I'm given the code: #include <iostream> using namespace std; class InventoryTag { public: InventoryTag(); int getQuantityRemaining() const; void addInventory(int numItems); private: int quantityRemaining; }; InventoryTag::InventoryTag() { quantityRemaining = 0; } int...

Hello, me and other engineering students at my university are designing an electric aircraft and we are hoping to implement the technology that NASA is currently working on, http://www.nasa.gov/press-release/nasa-electric-research-plane-gets-x-number-new-name Basically how it works is you have...

Picture a piping system made up of threaded steel pipes. It is to hold regular water at 7-10 bars. When testing the system for leaks, air is used due to a frost issue and the consequences of a larger leak with water. But what holds water doesn't hold air, and so it slowly leaks out. The question...

Dear All, how to know whether electronic components such as spectroscopy amplifier (canberra 1413 or 2010), single channel analyzer (from ortec) and NaI Scintillator counter with its basis are working good. Are there any testing methods using a oscilloscope. I have a Mössbauer radioactive...

As an exercise, I am trying to solve the 2nd-order wave equation: $$ \frac {\partial ^2 E}{\partial t^2} = c^2 \frac {\partial ^2 E}{\partial z^2} $$ Over a domain of (in SI units): ## z = [0,L=5]##m, ##t = [0,t_{max} = 5]##s, ##c = 1## m/s and boundary/initial conditions: ## E(z[0]=0,t) =...

I am currently in Honors Physics 3 which is the third introductory course of my physics degree program and covers modern physics beginning with special relativity. So far we have covered Lorentz transformations and velocity additions, relativistic energy and momentum, blackbody radiation, photon...

I just want to check my sanity... I am going to be testing some transistors in a lab very soon per the above mil std. The test methods range from Vce, Vbe, hfe and the breakdown voltages that are listed on the datasheet. The transistor at this point is irrelevant. Here's what I need to...

Is there any importance of mechanical testing ? and what are the types of mechanical testing?

I'm asked to design a rod, it is aluminium and it is to withstand force of 200kN. maximum allowable stress is 170MPa with a strain of 0.0025mm.mm^-1 rod must be at least 3.8m long but must deform elastically no more than 6mm when the force is applied. UTS = 170 MPa e = 0.0025mm.mm^-1 F = 200kN...

I feel the need to make sure my Dobsonian scope is working at its best. I was considering a conventional (?) red LED collimator but I suddenly begin to see these Artificial Stars on sale. Would that be a better way to go? Anyone have experience of them? Looking at real stars tells me that the...

is the function x²+3 surjective for real numbers. how do you test for surjectivity in general?

I got one correct for my code...what i am missing...any tips or guide? Write a unit test for addInventory(). Call redSweater.addInventory() with parameter sweaterShipment. Print the shown error if the subsequent quantity is incorrect. Sample output for failed unit test given initial quantity is...

The criteria for testing for convergence with the alternating series test, according to my book, is: Σ(-1)n-1bn With bn>0, bn+1 ≤ bn for all n, and lim n→∞bn = 0. My question is about the criteria. I'm running into several homework problem where bn is not always greater than bn+1, such as the...

can you perhaps explain in technical detail?

Hi PF, I hope I'm doing this right, first post. I need help with a research project for the effect of the ambient vibration frequency at resonance for a piezoelectric energy harvester (It's well documented, I know, but I have to do an experiment with it anyways). Anyways, I noticed that...

Hi Guys, I am having issues trying to repair this amp. http://www.tangible-technology.com/schematics/fender/HR-Deville/Hot%20Rod%20DeVille.pdf A little history is in order I guess. I have not been working on guitar amps for too long, several months now. I have repaired perhaps fifty or so...

Is there an experiment you can do at home to test whether a pair of sunglasses blocks UVA/UVB wavelengths? It says total UV protection but that could mean anything and I don't want wrinkles.

Hi All, I am trying to understand better the tests used to determine the existence of a linear relation between two variables X,Y. AFAIK, one way of testing the strength of any linear relationship is by computing ##r^2##, where ##r## is the correlation coefficient; this measures the extend to...

I was developing a physical RNG and I was trying to test it using The Chi-Squared test and The Kolmogorov-Smirnov Test. The latter gives me some problems. I have an attached photo with a table. In the table, n is the number of generated numbers. The book says that the test should be run for...

For our physics class we have to design an experiment investigating the factors affecting an electromagnet's field strength. I have decided to investigate the number of coils in the wire. My only problem is, I'm not sure how to measure the field strength. Our teacher gave us two things which we...

During the application process for graduate schools, I have the option of uploading GRE and TOEFL score reports that I 'printed to pdf' from the website. The score reports also show the other schools I sent official score reports to. I was wondering if the admissions committee could use this...

Hi. I have to test a couple PSUs (ripple, regulation, etc.) that are rated 12 V 62.5 A. In order to do so, I need a test load; I was thinking about using nine 2 ohm 100 W 5% resistors (about 3 usd) in parallel (giving 0.22 ohm 900 w). Taking into account the tolerance of the resistors, I get a...

I'm trying to implement a study plan for the upcoming school term. Currently I have study time, for three classes (totaling 12 credit hrs), slotted from Tuesday through Friday for three hours of studying each day. Alternating between classes each day (i.e. on Tuesday this class and on Wednesday...