Accuracy Definition and 236 Threads

The following appears as part of an intro to statistical significance. I don't quite get it and hence the appeal for clarification. Someone claims that a newly invented medical test T is 99% accurate. To check their claim the test is conducted among 100 subjects and in 95 the result is...

The above was part of a conversation on ##\pi## and the implication seems to be that the more accurate the value of ##\pi## in our calculations in an engineering context, the more circular our construction. Questions: 1. Is this true? More accurate values of ##\pi## allow for construction of...

I use a fork to tune my violin. The school teacher uses an ekectronic tuner which is low. I tried an app tuner on my phone. It is also low. How do I confirm for the teacher that these electronic tuners are not correct?

Was watching a Sean Carroll video and his answers to some questions seemed to run counter to the norm. For example at 1:15:30 in the video, he seems to be saying that we'd see only a (hypothetical?) 'test particle' get stuck at the event horizon of a black hole. Also at 1:17:19 in the video...

I am new to statistics and recently learned about ISO guidelines for Accuracy & Precision and Uncertainty & Error. But there are some graphs of probability distribution I found on internet which I am not able to grasp. image Source Q. In this graph(above) if...

I often wonder what the accuracy is when dealing with spacecraft and wondered how accurate a craft needs to be positioned into the Lagrange (L1,L2,L3) positions. Are we talking plus or minus 1km/100km/1000km etc. It's just that the system is so vast and what instruments are used to achieve a...

I find the values of the fundamental constants here https://physics.nist.gov/cuu/Constants/ In anticipation of the data of 2022, I want to clarify one point. Planck's constant is related by an exact expression to some other fundamental quantities: $$h = \frac{\alpha^2 m_e с^2}{2R_c}\qquad (1)$$...

A longer pendulum swings slower. So changing the length l of the pendulum changes the period T, which affects the timekeeping accuracy. But the problem is talking about the body on the spring, not the string. So the second formula cannot be applied here directly and I don't know how to progress...

Here are the codes(not all might be present, take it with grain of salt). https://github.com/prabesh-regmi/Employee-Promotion-Prediction

Is the accuracy of 10^-12 s achievable in measuring a neutrino's speed with current experiments? I have come across a number of papers stating the accuracy is in the order of nanoseconds. This is much lower accuracy than the measured speed of photons. I believe it is due to the difficulties in...

If I need to make a measurement to check compliance e.g. measuring component dimensions. How do I know what accuracy is required for the measuring instrument if the tolerance is not specified? For example, during an engine rebuild, the manufacturer specifies the valve stem diameter to be...

Hello, All measurement instruments have a finite accuracy. For example, a thermometer may provide a temperature measurement that is +-2F from the "actual" and true temp value. For example, if the reported measurement is 70F, the actual temperature may be between 72F and 68F. That said, let's...

The area of a circular disc with radius ##r## is ##A=\pi r^2\;\mbox{cm}^2##. A smith must make a circular metal disc of ##400\pi\;\mbox{cm}^2## with an accuracy of ##\pm{5}\;\mbox{cm}^2##. Which accuracy range must have a ##20\;\mbox{cm}## disc? Answer The metal worker wants to obtain ##|\pi...

Here's the story: I did the 23&Me and it told me that I was about 90% X but then there was among the smaller %ages a Y = French Later, about a year later, I checked it again. The French ancestry had disappeared. There was still 90% X, but now I had a Y = Scandinavia. So, I ran the test again...

I'm trying to understand the detailed concept of why the density of states formula is accurate enough to calculate the number of quantum states of an energy level, including degeneracy, within a small energy interval of ##dE##. The discrete energie levels are calculated by $$E = \frac{h^2 \cdot...

I'm trying to dynamically model the scenario of a disease spreading across the population, modelling the number of cases, and I would love to hear your feedback. It's kinda different from the S-I-R model, and its also a crude model. First, we consider two numbers, NT and NA. NT is the total...

How is a Scientific law or theory's accuracy tested? I've searched online about verification of Newton's law but the materials are unhelpful. Many show an experiment that verifies a particular instance of the law and then concludes the law is verified. We all know that there are infinite...

Me and some colleagues discussed accuracy of measurements. We didn't agree on how to treat the accuracy if two values are used to find the value, i.e. the difference between two values. Situation (explanation) The weight of a mass m of approximately 5 μg is to be scaled. The scale has an error...

With all the earthquakes going on in CA - and that the last one (7.1 mag) was strong enough to possibly trigger a small quake along the LA coast (i.e., as in LouisianA, not Los Angeles) - I was wondering about this. These instruments are so sensitive that they have to pick something up, even in...

In the Tipler & Mosca textbook we are shown how numerical integration (the Euler's method species of it) is done using a spreadsheet program. The authors then go on to say on page 138 that the accuracy of this program can be estimated by first calculating the values for a time interval of 0.5s...

This is a podcast and it can be found here. Basically, an interview of Nate Silver, the stat head behind FiveThirtyEight.com. They have made thousands of predictions on politics and sports (which they publish) and consider their competition to be betting sites and other modelers. Nate used to...

This is a problem I got for a review in probability and statistics The layout of the data is as follows: A B C D Order Accurate- 315 277 234 120 Order not - 34 50 35 18 accurate Like I said previously this is an or...

Used a P100 to pipette 93.6 micro-litres of fluid. There was an air gap in the pipette tip the first time I did it but no air gap the second time. I'm assuming there shouldn't be an air gap but can somebody tell me for sure?

Hi, I have a roughly 1.1 GHz signal to be downconverted to 100 MHz by mixing it with a 1 GHz local oscillator. I am not sure how to choose the performance of the LO. In particular: let's assume the LO has a jitter of 100 fs rms. At 1 GHz this corresponds to a frequency error of 100 kHz. Does...

Sorry that's the best wording for a title I could come up with. Anyhoo my question is one that I have wondered about for a long time, and I am prompted to post now after seeing this article on the new atomic clock. Let's assume that we have clocks that can measure time to an arbitrarily...

Homework Statement Two different scientists measured the speed of light four times. Scientist A 3.80*108m/s 3.32*108m/s 3.10*108m/s 3.05*108m/s Average 3.32*108m/s Scientist B 2.90*108m/s 3.10*108m/s 3.24*108m/s 2.95*108m/s Average...

What is the preferred method of measuring how accurate the normal approximation to the binomial distribution is? I know that the rule of thumb is that the expected number of successes and failures should both be >5 for the approximation to be adequate. But what is a useful definition of...

I currently have a cheap digital scale that will measure, say, from 1 g and beyond to the hundredth place with reasonable accuracy, but for anything less than a gram, it is erratic. For example, when I'm adding 0.15 g of a chemical, sometimes the value will change but often it will not and...

On a piece of equipment, I purchased new, the digital clock ran slow. The second digital clock that was installed ran slow---it lost approximately 4.1 minutes in one month. Below is what I sent the Service Manager who I understand thinks it is possible to test the newly installed clock...

A little background: Inspection room is kept at 20 C +/-2 C. Temperature gauge is accurate to +/-.5 C. Outside ambient temperature where parts are kept can vary from 5 C to 38 C. One part in particular is a rotor made of 4340 steel, ~2350mm long, average diameter of 115mm, and weighs ~ 650lbs...

The Variational Method allows us to obtain an upper bound on energy of the ground state (and sometimes excited states). Is there any way of determining an upper bound on the error of the energy obtained by the variational method without an analytic or numerical solution to the problem? i.e. Is...

I'm trying to measure high voltages with a DAQ card. Obviously I'm going to have to attenuate the voltage, but I need to make sure that I can measure accurately (within 1%) The code width of the DAQ is Vcw = 20Vpp/2^16 = 305.176uV For this code width to be within 1%, the minimum voltage I...

Homework Statement How big must N be for the simple version of stirlings formula to be accurate to within 2% Homework EquationsThe Attempt at a Solution So I think the starting point is ##\frac{N lnN-N}{lnN!} =\alpha ## where ##\alpha=0.98## But i have no idea how to solve this expression...

Hi everyone. I read from: https://www.nucleonica.com/Applet/NaturalRA/Button5/page5.html that inside the human body, 4400 of K40 atoms disintegrate every second through radioactive decay. Of this decay, 11% (480) results in gamma radiation, and 50% of that 11% (240) escapes the body. My...

The website of CIAAW list the 2012 atomic mass in Daltons (Atomic Mass Units) and mention the atomic mass of stable isotopes followed by an additional number between braces. For example Helium-4: 4.002 603 2541(4) My first question is what does the number between braces mean? I assume it is some...

Homework Statement We performed an experiment to see which laboratory glassware was more accurate and which was more precise. Question: (a): Which glassware was more precise and why? (b) Which glassware was more accurate and why? Use the calculations to support your statement. I won't post the...

Is there any difference in accuracy with using a resivoir vs just the tube? I want to acurately level the torque boxes on my car on jackstands so i can make frame measurements. Thanks

How accurate do you think NASA's eclipse calculations are? Will that aircraft provide accurate moon trajectory?

Can anyone tell me accurately. accuracy of moon orbiting Earth in how many days and hours and seconds and if it is multiplied by 14 how much it will be in days. i need accurate answer. Thanks, Ahmed.

Imagine a single slit with plane light waves incident on it with a screen (ideally far enough from the slits to simplify the math). According to Kirchhoff's diffraction formula, when a very wide slit is doubled, average intensity (averaged over all diffraction angles) doubles, and so does E_peak...

During a lab exercise we measured different masses of a magnetic material on a scale while changing the strength of the magnetic field it was in. Afterwards we plotted the masses and the fieldstrength hoping to find a linear slope. Then we drew a linear slope by using linear regression and found...

During a labexercise we measured a value to be 26.3 mT. The teslameter was said to have an accuracy at +- 0.05%. This means we measured 26.3 +- 0.0132mT. However we are supposed to write a measured value with it's error in the last digit. But the error is smaller than the smallest digit we got...

I have 2 PERFECT data of the transmitter and receiver. From 2 data, I can calculate the delay estimation: Fs = 8e6; % sample rate ... for i = 1:2 [cc_correlation,lag] = xcorr(signal2(i), signal1); [cc_maximum, cc_time] = max(abs(cc_correlation)); cc_estimation...

Hi, For my project I am plotting a Force vs Displacement graph using 2 analog inputs which are going to a DAQ. The two analog inputs are coming from; -A 5k potentiometer (for the displacement) -A 1000 lb load cell sensor (for the force) I would like to use a regulated 12V DC (1Amp) power...

I have a concern about having some wave function psi, that is originally a superposition of many eigenstates (energies). Traditionally, it is said that the square of the coefficient of each of the component eigenfunctions represents the probability of measuring this particular energy eigenstate...

i've seen the double slit experiment and the delayed choice . my mind rejected the conclusion, but the experiment setting and configuration of delayed choice is rational and holds water so i accepted the experiment outcome even if it means the world isn't real. i had to give that intro that...

I have a 1968 Mustang that I bought at auction from my grandfather's estate it is almost completely apart and I want to rebuild it for him has sadly he ran out of time, I have a reproduction manual from 1968 with frame dimensions in it and some of the dimensions car vertical to a datum line. I...

Hello, I recently did the Franck-Hertz experiment (a short summary of the experiment can be found here http://inpp.ohiou.edu/~roche/3701_web/man-fh-a3b.pdf). I am currently doing data analysis and am having a hard time determining the accuracy of the oscilloscope, the Tektronix TDS2004B. I am...

I was wondering why arrows deviate away from the target. If the arrow aimed at an object it usually lands above the object. Also if the mass of the arrow is increased it seems to get more and more accurate. Could someone explain why this happense?