Testing Definition and 589 Threads

Homework Statement Classify the fixed points of the following linear system and state whether they are stable or unstable \dot{x}=x + y \dot{y} = x + 3y Homework Equations The Attempt at a Solution Fixed point at dy/dx = 0/0. Therefore fixed point = (0,0) How does one test...

How is hypothesis testing performed for multivariate data? Say for simplicity we have two iid draws from a binomial distribution Bin(10,q) with X1=7, X2=8. Under the null hypothesis H0:q=1/2, the individual p-values (as one-tail probabilities) are approximately 0.172 and 0.055 respectively...

Hi I'm not a physicist but I'm looking for a simple way to test the hardness of different materials. I need to do a demonstration and collect results with a science class, the task sheet that accompanies the lesson says to place a cloth over the materials and hit them with a hammer. I would...

The experiment Einstein proposed that supposedly proved successful kind of confuses me. If you can prove a beam of light bends when near the sun, how can we prove that from Earth with a picture because by the time we're able to see it to take a picture, the light has already gone passed the sun...

Hi! I was hoping someone could answer a quick question I had about science fair... I had talked to my teacher about doing a project where I test the reaction rate of enzymes in turkey giblets (see which chunk of the turkey has fastest/lowest reaction rates) but we didn't go into a lot of detail...

I have found an interesting infinite sum that appears to converge to a number. In fact, I have created four of these using slightly different rules. Since, all of the odd primes are involved in each series, I know that the series are infinite. I will confirm this by using Euler's Prime...

Please can anybody explain why Impact testing is carries out @ -20 degree or @ lower temparatures. & what will happen if it is conducted @ higher temp. Please elaborate.

I just want to test/verify my knowledge of change of basis in a linear operator.. (it's not a homework question). Suppose I have linear operator mapping R^2 into R^2, and expressed in the canonical basis (1,0), (0,1). Suppose (for the sake of discussion) that the linear operator is given by...

Hi, I am wondering if anyone out there has some experience testing semispan wing models in a tunnel. Most of my tunnel experience is 2D testing such as airfoils but I am going to be starting some 3D wing tests soon and I would like to know what sort of issues to expect. For example I have been...

This is a very silly question. I can't believe I have forgotten. I have a 30v bench power supply and I am looking to test an op-amp running at +/- 15v. I have a supply which has a negative output/ positive output and inbetween a green common/earth output. How do I wire them to produce the +/-...

Does anyone have any comment on the usefulness of the following test? Input P Prime = true Triangular = 0 n = 0 Do until Triangular > P n = n + 1 Triangular = Triangular + n loop X = Triangular Mod P Do Y = Int(Sqr(2*X)) ' Comment if X is triangular then (Y*Y+Y)/2 = X If (Y*Y+Y)/2 =...

Homework Statement Determine whether \sum\frac{1}{(2^{n}-n)} from n=1 to infinity converges or diverges. Homework Equations a_{n} converges if \stackrel{lim}{n\rightarrow\infty}\left|\frac{a_{n+1}}{a_{n}}\right|<1. The Attempt at a Solution I'm really having a tough time knowing...

"The holometer"-- experimentally testing the holographic principle? Several popular-science type news sources are reporting this weekend on an experiment at Fermilab that claims to experimentally test the holographic principle.. Popsci then says a bunch of vague stuff that sounds like they...

urgent help needed: compression testing hi guys, I have some homework problems about compression testing, please kindly help me out, I need to complete them by tomorrow but I have struggled for days... 1. what are the possible fixtures for compression testing? --- contrast them with those...

I go to a sort of the middle of the road university and test averages in my classes can be quite low(50s or so) but I almost always do significantly better than average and have one of the highest scores in my classes. I have a hard time telling if this means my peers don't work very hard/aren't...

Hey I have a neural network model that produces as an output a vector of 169 variables which represents the probabilty of having a certain hand in poker (2 random cards dealt from a regular deck - 169 possibilities if considering only if the cards are from same suit or not). The model...

Homework Statement A student attempts to measure the gravitational constant G by suspending two 100.0kg spherical masses from a high ceiling in a shopping center and measuring the deflection of the cables from the vertical. The cables are 45.0m long and attached to the ceiling 1.00m apart...

Has anyone here looked at this paper? Testing Newtonian gravity with distant globular clusters: NGC1851 and NGC1904 R. Scarpa, G. Marconi, G. Carraro, R. Falomo, S. Villanova http://arxiv.org/pdf/1008.3526v1 (Submitted on 20 Aug 2010) Globular clusters are useful to test the validity...

Hi all. Iam trying to find out an mass-damper-spring equations for a 1-DOF mechanical shaker for the purpose of plant model equation.Further, this equation is used in kalman filter algorithm with measurement model of an accelerometer. Can anyone help? Thanks in advance...!

I'm currently doing a testing on hand pump from 2 different brand. Let's say Brand A and brand B. Brand A hand pump is 20cc/cycle with maximum pressure 350 bar, Brand B hand pump is 25cc/cycle with maximum pressure 350bar as well. 1. brand A hand pump easily pump up to 92bar, but after i tried...

Hi, I've just bought 15,000 meters of Foil Twisted Pair cable (2 PVC insulated conductors and a Drain wire with Aluminum Foil around them) and I'm trying figure out if it will be good enough for Cat 5. How should I test it without having to chop it down to smaller pieces? The test...

Test the following Series for Convergence (absolute or conditional) or divergence ∑ (-1)^(n)/ (1+1/n)^(n^2) I know we solve it with the root test but i reached at a point where i don't know how to cancel it out ---- lim(n--> infinity)= 1/(1+1/n+1)^(n+1^2) *[ (1+1/n)^(n^2)]/1...

If I have 4 variables in my multiple regression and I'm told to test whether one is significant, and 3 others are not what would I do with the one left over? I thought it would be easy as I could just test whether for H0: variable 1>0, variable 2,3 =0 But what if I'm told to restrict...

Homework Statement Use special comparison test to find if \frac{2+(-1)^n}{n^2+7} is convergent or divergent.Homework Equations Special comparison test using the convergent series \frac{1}{n^2} and taking the limit as n-> infinity of my initial series \frac{2+(-1)^n}{n^2+7} divided by my...

Homework Statement A simple device that is used to test the strength of antifreeze in cars consists of a small tube that has several small, coloured spheres inside it. When antifreeze is admitted into the tube, some of the spheres will float, giving an indication of the strength of the...

Hello, I want to do a test heating a hot dog in a tube using a Magnetron from a 900W Microwave oven. Before doing the test I would like to know if there is any reasons not to mount the magnetron antenna on top of the metal tube, or on the side. (Please see attached picture) Also, will I...

I'm writing code to check if polygons intersect, but I've ran into a problem. I have two "vectors." Each has an origin and x and y components. They are facing towards each other. I need to write code that determines if there's a perpendicular axis that separates them. Here's a picture of what...

Boolean Algebra: Everyone will now about the situation once Jay starts gossiping. Leon is upset because everyone knows about the situation. Since Leon is upset, May is unhappy. Therefore, May is unhappy when Jay starts gossiping. I attached my working and I said it was invalid as line...

Hi, if I have some spread over a very small range of binned values, how can I test if the distribution is normal. Basically if it weren't, then the data would be fraud data. Is there a way to calculate something like a probability that the data was not manipulated and is correctly given by the...

Homework Statement We want to test wheter 40% of Kentuckians prefer popcorn as their movie snack of choice. a randon smaple of 100 movie goers shows that 55 of tehm pick popcorn as their favorite movie snack. Check the normality conditions, state the hypothesis, and state your conclusions...

It suddenly occurred to me that I've never heard of a test of the Equivalence Principle itself - such as something like ... An accelerating laboratory [in space] can see very obvious effects in external astronomical observations. Depending on the rate of acceleration, there would be...

Homework Statement If \sum_{k=1}^{\infty} a_k converges and a_k/b_k \to 0 as k\to \infty, then \sum_{k=1}^{\infty} b_k converges.Homework Equations It is true or false.The Attempt at a Solution I think it is false and here is my counterexample. Let a_k = 0,b_k=\frac{1}{k}. This satisfies our...

Homework Statement This is probably a really simple question , but how do i test my eigen values to see if there right ,---------- (A-tI)x=0 where t is an eigen value , I know how to test if my eigen vectors are correct but how do i test to see if my eigen values are right ...

In one of my events for Science Olympiad, I am given a water sample and must test for certain anions and cations. This wouldn't be a problem, except for the only chemicals we are given are HCl and NaOH. We are provided kits for certain ions, like phosphate and nitrate, but on the last test we...

In an experiment, students were testing their hearing range and found that it averaged about 25 Hz to 18 000 Hz. What are the wavelengths of sound waves producing these frequencies in air where the speed of sound is 343 m/s? Would I use the formula wavelength= velocity/ frequency...

Hello! Right now I am trying to figure out how much of an affect dust has on the power production of some solar cells that I have. I was just searching for a possible material to use for dust testing. Anyone have any bright ideas?

I've got a couple of problems I'm stuck on. Any help gratefully received! Test for convergence/divergence: \sum_{n=1}^{\infty} \frac {(n+1)}{n^3 ln(n+2)} What test should I do here? Can I rearrange the equation to be: \frac{(\frac{1}{n^2} + \frac{1}{n^3})}{ln(n+2)} and then use...

Hi all, We have a bearing pad at work that failed a porosity test and could not hold pressure (this was the pad itself and not the babbit surface). I need to look into some NDT testing that will give us an idea about the porosity. I have googled and some sites say different things, from...

when i have a system of only dependant sources and i want to find its norton /thevenin representation i need to add a testing source on the ports from whome we want to see the reaction how to know that i should put a voltage source or current source ?

Here's what I understand by flux: \int \textbf{F} \cdot \textup{d}\textbf{A}, the surface integral of a vector field. I gather the vector field that's integrated to give a flux is called the flux density (examples: the magnetic B field for magnetic flux, the Poynting vector for...

Homework Statement A yacht is of length 5m and travels at 10m/s. A scale model of length 0.5m is tested in a tank in order to predict drag on the yacht. Assuming that the fluid density and viscosity are the same for the yacht and model, can we obtain similarity? What is our best value for...

Homework Statement If \lim_{x\rightarrow c} f(x) = f(c) for all values of c, 0<or= c <or=5, and f(0)\neqf(5), which of the following could be false? A. f(4) exists B. f'(1) exists C. \lim_{x\rightarrow2^+} f(x) exists D. \lim_{x\rightarrow3} f(x) = \lim_{x\rightarrow3^+} f(x) E...

Homework Statement A cola company's long-term market share is estimated to be 45%. After an extensive advertising campaign, 68 out of 150 customers surveyed claimed to have purchased this company's cola recently. Was the advertising campaign a success? justify your assessment Homework...

There is a standard impact test that is used in the fenestration industry. An air cannon is used to fire a piece of lumber at the unit being tested. The mass of the 'missile' is 4.09 kg. The velocity of the missile is 15.26 m/s. I am wondering if there is a way to approximate this test...

I know this seems like a homework question but the last time I was in a physics class was <ahem> 1982. For product testing reasons, I have fabricated a (rough, very rough--no laughing at the fabrication/welding) 'repeating pendulum hammer'. Please see "test rig diagram.jpg" Distance from A to...

Can the Test for Divergence (limit of an->infinity not equal to zero) be used on an alternating series? For example, if a series has a (-1)^n term. Can we assume that since the limit of that term does not exist, then the series is automatically diverging?

please anyone can help me how make check the linearity and shift invarient for the system I want to determine whether the system is linear and shift invarientby steps g(m,n) = f(m,-1) + f(m,0) + f(m,1) g(x) = (integration from +infinety to - infinety) f(x,z) dz please help me...

Hi all ! What chronology of Bell inequalities testing ( their violation ) ? What positive and negative aspects of each experiment ? What experiments have been spent latest years ? Some material: http://arxiv.org/PS_cache/quant-ph/pdf/0310/0310192v1.pdf Thanks.

Homework Statement A drug company markets a medication that cures about 60% of cases with depression. A CB program is thought to be more effective. It was delivered to 15 depressed people. Determine the minimum number of cured people required to support the claim that the CB program is more...

Hi all, I was thinking recently about insulin testing, and whether the convenience could be extended to other hormones and biochemicals in the body. For instance the thyroid molecules T3 and T4. It seems like a device capable of testing for the level of these molecules on the fly would be...