Test Definition and 1000 Threads

  1. L

    I Calculating Delta Values: Paired t Test

    Using paired t test, how should I pair these results? To calculate the delta values, should I use: downstream - upstream for both sep and apr ? or upstream (sep) - upstream (apr) and downstream (sep) - downstream (apr) ? Thanks
  2. Entertainment Unit

    Test the following series for convergence or divergence

    Homework Statement Test the following series for convergence or divergence. ##\sum_{n = 1}^{\infty} \frac {\sqrt n} {e^\sqrt n}## Homework Equations None that I'm aware of. The Attempt at a Solution I know I can use the Integral Test for this, but I was hoping for a simpler way.
  3. L

    How to take into consideration errors in the Mann-Whitney test?

    I have 2 independent samples (groups), each group contains 10 experimental values of variable T and their standard deviations (errors). I need to do intergroup statistical analysis, i.e. to elucidate whether there is significant difference between 2 groups in terms of variable T. I chose...
  4. opus

    I Looking for help to understand the Integral Test

    Please see the attached images that reference the text. To my understanding, we wish to use the integral test to compare to a series to see if the series converges or diverges. In these two examples, we use ##\sum_{n=1}^\infty \frac{1}{n}## compared with ##\int_1^{k+1} \frac{1}{x}dx## and for...
  5. MathematicalPhysicist

    I A question regarding the ratio test for limits

    So we have the theorem: if ##a_n>0## and ##\lim_{n\to \infty} a_{n+1}/a_n = L## then ##\lim_{n\to \infty} a_n^{1/n}=L##. Now, the proof that I had seen for ##L\ne0## that we choose ##\epsilon<L##. But what about the case of ##\epsilon>L##, in which case we have: ##a_{n+1}>(L-\epsilon)a_n## but...
  6. opus

    Does the series converge using the integral test?

    Homework Statement Use the integral test to compare the series to an appropriate improper integral, then use a comparison test to show the integral converges or diverges and conclude whether the initial series converges or diverges. ##\sum_{n=3}^\infty \frac{n^2+3}{n^{5/2}+n^2+n+1}## Homework...
  7. R

    Four-point flexural test - Please help me understand

    According to wikipedia, this is how to calculate flexural stress where "the loading span is 1/3 of the support span (rectangular cross section)": stress = force x length / (width x (depth x depth)) Stress ("outer fibers at midpoint"), (MPa) Force ("load at a given point on the load deflection...
  8. e2m2a

    I Euclid's Formula as a test for sufficiency

    If anyone side of a triangle cannot be derived from Euclid’s formula for pythagorean triples, is this sufficient to prove that a right triangle with integer sides is impossible? For example, let's take the leg expressed by k2mn in Euclid's formula,, where k,m,n, are integers. If one of the...
  9. yecko

    One-factor-at-a-time test matrix

    Homework Statement If Z(X,Y) = (X^2+Y^2)*(P(X) + Q(Y)), how to convert it to one-factor-at-a-time test matrix ? Write down the relevant formula and give a brief explanation. Homework Equations below: in my attempt The Attempt at a Solution Z(X1,X4) =P(X1)*Q(X4)...
  10. Vital

    B Chi-squared test stat choosing a critical value

    Hello. I am doing problem sets on very basic stat topics. When solving problems that require the use of chi-squared table, I stumbled upon an unexpected issue. I seem to miss something important about how to correctly choose the right critical value using the chi-squared table. Below are two...
  11. Y

    Integral Test: Analyzing $$\sum_{n=3}^{\infty} \frac{1}{n^2-4}$$

    Homework Statement Use the integral test to determine whether $$\sum_{n=3}^{\infty} \frac{1}{n^2-4}$$ converges or diverges.The Attempt at a Solution [/B] Taking the integral we have $$\int_{}^{\infty}\frac{dn}{n^2-4}$$ Note: Mary Baos text is having us write the integrals without lower bounds...
  12. J

    Force on a stationary test charge from a moving charge

    Given a test charge, let's say on the vertical y axis. Another charge vertically below it moves past at a significant speed compared to c. From the Lorentz transformations (in most E&M books) the electric field and thus the force on the test charge will be greater than would be the static...
  13. K

    Generator tripping on ground fault during load test

    We have been testing a Cummins VTA-1710-G2 Diesel Generator 1800 RPM 480 Vac 671 kW with an Avtron K580 load bank that is hooked up to our three 480 Vac output cables and one cable to our facility ground. The generator output breaker keeps tripping when the load is around 350 kW. The test...
  14. Y

    MHB Power Series (Which test can i use to determine divergence at the end points)

    Hello, I was given f(-4x)= 1/(1+4x), and I used the geometric series to find the power series representation of this function. I then took the limit of (-4x)^k by using ratio test. The answer is abs. value of x. So -1/4<x<1/4 I then plugged in those end points to the series going from k=0 to...
  15. K

    Using the Integral Test to Show Sum is Less Than pi/2

    Homework Statement Use the integral test to show that the sum of the series gif.latex ##\sum_{n=1}^\infty \dfrac{1}{1+n^2}## is smaller than pi/2. Homework EquationsThe Attempt at a Solution I know that the series converges, and the integral converges to pi/4. As far as I´ve understood...
  16. Y

    MHB Calculus 2 (Power Series) when the limit is zero by root test

    Hi guys! Here's a problem i was working on. I solved it by root test and got absolute value of x on the outside of the limit and the limit equaled zero. Is it wrong to multiply the outside absolute value by the zero I got from the limit? or is that okay? In general, when we are solving power...
  17. J

    Energy transition of LiCl from flame test

    Homework Statement LiCl flame test is red. a) define what process b)and transition between which energy levels?2. The attempt at a solution a)I believe that the process would be emission, as photons are emitted when energy is released b)n=2 to n=1 I assumed that that would be the lowest energy...
  18. Z

    How to Manually Test Solidity Code Converted into F-star?

    Hi, I read a research paper for verification and validation of solidity code. It uses F* (F-star). However, it has to convert the solidity code into F-star. I can't find the converter. Can some body please guide me how to manually test the code? Code is given below: contract MyBank {...
  19. J

    Magnesium Carbonates Reaction Under Various Test?

    Homework Statement If you had a solution of Magnesium carbonate, what results would you expect from the following four tests: Precipitation Test, Flame Test, Benedicts Reagents Test, Dilute Acid Test. Could someone take a look at my reasoning to how the Magnesium Carbonate would react under...
  20. L

    A Higher Order Derivative Test and Germs

    If ##f'(0) = 0## and ##n## is the smallest natural number such that ##f^{(n)}(0)\neq 0##, then the higher-order derivative test states the following: 1. If ##n## is even and ##f^{(n)}(0)>0##, then ##f## has a local minimum at ##0##. 2. If ##n## is even and ##f^{(n)}(0)<0##, then ##f## has a...
  21. G

    Why a D-D reaction in the Divertor Tokamak Test Facility?

    The DTT project proposal talks about a D-D reaction inside the future tokamak that is going to be built in Italy, Frascati. Which is the reason of this choise? The cross section is smaller than the D-T reaction one, and neutrons are less energetic. How this influences heat and particle exhaust...
  22. J

    Bench test AC transformer from stereo tube equipment

    I would like to disconnect the secondary windings from a stereo preamp to test the voltages of the secondary windings. The transformer has a 330 - 0 - 330 volt center tapped secondary and a 10.9 volt secondary. It is to be used with house current - 110 or so in Virginia. I have measured the...
  23. G

    Insulation test of a long cable

    In order to do some welding a long way from a power socket, I have made up a 200m long ‘extension lead’ from some 6mm2 armour cable. The cable is needed for another job later on. I have an test unit that: 1. Checks earth/ground bond with 8Vac and 25A. 2. Then measures insulation resistance...
  24. D

    Tensile Test of Slip Ring - Working out Tensile Strength

    All, Through work, I've recently been tasked with investigating a very old tensile test technique, according to BS HC 403:1977 (now withdrawn). Essentially, you take a ring. Anywhere along it you make a slit all the way through. You then pull that ring in a tensile machine, ensuring that the...
  25. G

    Misc. Exploring Materials Engineering with DIY Test Machine & Arduino

    Hello there. I'm a veteran science teacher at the middle and high school level. I've taught a few years of physics and am interested in moving towards engineering. I have looked at a number of available curricula like Project Lead the Way which require a significant investment in time and money...
  26. S

    Pressure test containment wall thickness

    Hi If I know the velocity, mass and diameter of a missile from a failed pressure test how can I calculate the minimum thickness of a containment sheet steel wall say 1 meter away?
  27. T

    Will I Pass My Road Test on My Second Attempt?

    Hi, during my driving lesson today my road test instructor said that he says that he feels comfortable with me on the road test this time. This will be my second attempt at the road test and my 5 hour class is next sunday.
  28. adamaero

    TTL, voltage, one-wire test rig

    Spec My job, as an undergraduate EE student, is to create a test rig for offsite electronics (environmental sensors hooked up to a data logger, 12V batteries and solar panels). The test rig should be able to evaluate output from sensors (serial TTL, analog voltage, 1-wire) and output required...
  29. N

    A Two Bernoulli distribution- test hypothesis for biased coins

    I'm simplifying a research question that I have at work. Assuming I have 2 coins each with a different probability of head, let's call heads a success (p). Those are biased coins each with a different p, and I do not know the probability of success of each coin, but I do got a sample: Coin 1 -...
  30. TytoAlba95

    Understanding Widal Test Kit Dilutions

    This snip off is from Himedia Widal test teaching kit. I understand 1/20 1/40 1/80... are the concentrations in each test tube. They are obtained by the following calculation: (2nd testube) 1/2 X 1/20. But I can't decipher the numbers written at the top, 10-1 , 10-2 etc. Besides which of of...
  31. K

    B Geometrical Test for Immersion of Klein Bottle in Higher Dimensional Manifold

    I know that there exists non-geometrical proofs that the usual mapping of the Klein Bottle in ##\mathbb{R}^3## is an immersion. But I would like to see an actual geometrical 'test'. I was thinking if saying that on the self intersection, which I circled in red below, the map being injective can...
  32. uzi kiko

    A 2 samples T test in case of non-normal distribution

    Hi All I made an experiment where I measured the change of the impedance of a coil when I changed a environment parameter X times. For each change I collected ~20 samples. So I have a table with X lines that represent the number the change of the parameter and 20 columns that represent the...
  33. mishima

    I Test for dependence/independence of multiple variables

    I don't think this is related to linear dependence/independence of linear algebra. I am talking about multi-variable calculus. I am getting confused with being able to quickly tell which variables depend on others when there are 4+ variables involved. For example, suppose I have w(r,s)...
  34. M

    Car test, and vibrations problem

    Homework Statement in tests to choose the most comfortable shock absorbents, 3 cars are used, with the same mass "m", and the same springs, but different shock absorbents. the graphs show the changes in car height when passing over a bump (y=0 being the normal state of the car). . . . -Witch...
  35. Dan Card

    Schools Can you Test out of College Classes?

    So I finished my first year of college and I'll be transferring to a new college where a C or better is required. However my Intro to Anthropology(100) class I had an absolutely terrible professor who gave me a C- and so now it won't transfer and I'm out of $1,400. So my question is am I able...
  36. J

    Which of the following aqueous solutions would test closet to pH 7

    Homework Statement >Which of the following aqueous solutions would test closet to 7 on the pH scale? $a) NaCl$, $b) Na_2CO_3$, $c) NaH_2PO_4$, $d) NaCN$ Homework EquationsThe Attempt at a Solution I don't understand this. So I tried writing chemical equations like for a), NaCl + H20 --> NaOH +...
  37. DrChinese

    I Big Bell Test Collaboration: Challenging Local Realism with Human Choices

    Not sure if this reference has been posted yet, but I just saw it come through and thought I'd share. This is the "Big Bell Test Collaboration" using measurement choices provided by persons (as opposed to computer generated "random" choices). (The authors are a virtual who's who in the world...
  38. W

    A Defining a Symmetry Statistic to test for Normality?

    Hi, Just curious. One of the requirements for a data set to be normally-distributed is that of symmetry. Question: Is there or could one define a statistic to this effect, meaning to determine the level of symmetry on the data set and use that to determine at certain confidence level if the...
  39. C

    What happens to air in a hydrostatic test

    I am a contractor. I install water lines. Once installed we have to pressure test them. We pump the lines up to 150 PSI of water. If the PSI drops one of 2 things is wrong, either i have a leak in the line, or there is a small amount of air in the line. Generally if it is air, it stabilizes...
  40. Mr Davis 97

    I Proof of Alternating Series Test

    I'm looking at the proof of the alternating series test, and the basic idea is that the odd and even partial sums converge to the same number, and that this implies that the series converges as a whole. What I don't understand is why the even and odd partial sums converging to the same limit...
  41. isukatphysics69

    Comparison test of infinite series

    Homework Statement Homework EquationsThe Attempt at a Solution So the book is saying that this series diverges, i have learned my lesson and have stopped doubting the authors of this book but i don't understand how this series diverges. ok i can use the comparison test using 1/3n and 1/3n...
  42. Jschrodes4

    Single Cycle Pressure Test for Pressure Vessel

    Homework Statement I need to design a pressure test that, in one cycle, will simulate the 8000 cycles that a given pressure vessel will undergo. I know the dimensions and material of the vessel, the number of pressure cycles it will undergo, and the max and min working pressures. Homework...
  43. J

    A Sample Test | Component Lifetime

    Hi, I'm currently working on a project for which I have to determine the Life-Time of a certain mechanical component within a certain confidence interval. By sampling a small number (let's say n = 10) of these components and measuring the number of hours until failure, I want to determine this...
  44. J

    How Can I Test the pH of Foods and Drinks?

    i want to be able to test the ph of foods and drinks so I purchesed a digital ph tester for water. Is there a better ph tester option ? If I wanted to test the ph of something like mayonnaise would I just stick the tester into the mayo or would I need to mix the mayo with water first?
  45. J

    MHB Left-Tailed Test Rejects Null Hypothesis at 0.05 Level

    In a left-tailed test, the value of the test statistic is -2. If we know the shaded area is 0.03, then we have sufficient evidence to reject the null hypothesis at 0.05 level of significance.
  46. M

    MHB Hypothesis Test for Public Transport On-Time Claim with Example

    Hey! :o A public transport company claims that its buses are at least $95\%$ on time. (A bus is still on time here, if he has at most $3$ minutes delay compared to the timetable.) A sample size of $n = 1000$ at various stops results in $66$ delays. The probability that a randomly selected bus...
  47. I

    MHB Significance test comparing slopes from linear fit

    I would like to compare four slopes I got from linear fits through five data points for each fit. The fitting results (for the slopes) are as follows: 1: 0.08885 ± 0.00991 2: 0.08744 ± 0.0118 3: 0.10288 ± 0.00669 4: 0.0926 ± 0.01285 My hypothesis is that they are all not significantly different...
  48. Z

    Setting Up a 12V DC Test Stand w/ Controller & Cycle Count

    Setting up a test stand that will need a controller to cycles a device ON and OFF at an adjustable time interval (allows me to make the ON duration and OFF duration whatever I want). It will also need to keep a count, so I can track the cycles count and also set a limit on cycles so it will stop...
  49. Manoj Sahu

    Why do we use a Contact Resistance Measurement test?

    I was wondering about contact resistance measurment test. Why do we take such test?
  50. Rectifier

    Does this series converge? Using the limit comparison test

    The problem In this problem I am supposed to show that the following series converges by somehow comparing it to ## \frac{1}{k\sqrt{k}} ## : $$ \sum^{\infty}_{k=1} \left( \frac{1}{\sqrt{k}} - \frac{1}{\sqrt{k+1}} \right) $$ The attempt ## \frac{1}{\sqrt{k}} - \frac{1}{\sqrt{k+1}} =...
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