What is Estimate: Definition and 375 Discussions

Estimation (or estimating) is the process of finding an estimate, or approximation, which is a value that is usable for some purpose even if input data may be incomplete, uncertain, or unstable. The value is nonetheless usable because it is derived from the best information available. Typically, estimation involves "using the value of a statistic derived from a sample to estimate the value of a corresponding population parameter". The sample provides information that can be projected, through various formal or informal processes, to determine a range most likely to describe the missing information. An estimate that turns out to be incorrect will be an overestimate if the estimate exceeded the actual result, and an underestimate if the estimate fell short of the actual result.

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  1. A

    Estimate distance of neutrino

    Homework Statement...
  2. R

    Kalman filter a posteriori estimate covariance matrix

    I am having some trouble deriving the a posteriori estimate covariance matrix for the linear Kalman filter. Below I have shown my workings for two methods. Method one is fine and gives the expected result. Method two is the way I tried to derive it initially before further expanding out terms to...
  3. C

    How to estimate the power of a laser pointer

    Not sure if this is the right place, but I'm hoping to ask two questions: 1. I shine a laser pointer at a mirror at night, and the reflecting beam glaces off of my eye. Obviously it's quite bright, and I want to know if this has caused any serious damage. Of course I shut my eye, but apparently...
  4. T

    Estimate noise improvement as a funtion of sampling rate

    Hi all, I would like to estimate from my experimental data what would be the noise of the signal if I could sample at a higher rate. It is possible to do that? Do you have any references to good books that explain this topic? Thank you!
  5. A

    Population proportion from a sample estimate

    I am interested to know which proper statistical test to use to know the population proportion from a sample taken from the population. For example, a sample of 20 people with 7 persons prefer the red color and 13 prefer the blue color. Which of the following methods should be used to conclude...
  6. K

    How to estimate the power of laser beam

    I posted a question about Rabi frequency here https://www.physicsforums.com/threads/what-is-rabi-frequency.331082/ some times ago. The replies there answer some of my questions but I am still looking for detail explanation on the relation between Rabi frequency and the power of the beam. I read...
  7. O

    MHB What does priori estimate do in fixed point theory

    what does priori estimate do in fixed point theory ? plese, I want some examples :)
  8. F

    Estimate the Dielectric Breakdown of Air

    Homework Statement A capacitor is charged to V = 5 kV. A wire is then connected to one plate and is slowly connected to the other. Before actually touching the plate, a spark of length l = 1 cm shoots from the wire to the plate. Using this information, estimate the dielectric breakdown of air...
  9. It's me

    Estimate the latent heat of water

    Homework Statement Try to estimate the latent heat of vaporization of water and nitrogen using the Van der Waals model. What happens? Homework Equations $$ΔQ=TΔS=L$$ $$S=nR[\ln(\frac{(V−nb)T^{3/2}}{nΦ})+\frac{5}{2}]$$The Attempt at a Solution I predict the latent heat of vaporization of...
  10. shanepitts

    A simple astrophysics rough estimate exercise

    Homework Statement Homework Equations (mv2)/r=(GMm)/r2 --------(1) r≈8kpc≈2.47×1020m v≈220kms-1 The Attempt at a Solution Using equation (1) and solving for M I got M=(v2r)/G=(4.84×10102.47×1020)/6.67×10-11 M=1.79×1041 kg does this answer seem correct? P.S. This is not a homework...
  11. It's me

    Estimate the latent heat of water with Van der Waals

    Homework Statement Try to estimate the latent heat of vaporization of water and nitrogen using the Van der Waals model. What happens? Homework Equations $$\Delta Q = T\Delta S=L$$ $$S=nR\left[ \ln\left(\frac{(V-nb)T^{3/2}}{n\Phi}\right)+\frac{5}{2} \right]$$ The Attempt at a Solution I...
  12. B

    How do I estimate price of a design?

    How do I evaluate the price of the vibro-feeder that I'm modifying? I need to find out how much it would cost to create individual parts, i.e. 1.5mm formed steel or aluminum plate etc. I guess I should evaluate raw materials first but how much does the preparation costs, any reliable websites?
  13. M

    Error estimate for integral of interpolated function

    Hi, I have a project at uni where I am making an approximate analytical expression for a parameter and comparing the result with more rigorous simulations. The thing is: the parameter I am comparing is the 2d-integral of the results from the simulations over some area, and the simulation results...
  14. Y

    Estimate flattening of the Earth

    Homework Statement The flattening of the Earth is defined as f⊕ ≡ 1 - (Rp - Re) where Re is the radius of the equator and Rp is half of the distance between the North Pole and the South Pole. Estimate the flattening of the Earth. Homework Equations Fg = Gm1m2/r2 The Attempt at a Solution...
  15. Pull and Twist

    MHB Remainder Estimate for Integral Test

    I'm working on the following problem and I have made it this far... am I on the correct path or am I doing this incorrectly?? I find series extremely confusing. Also... how do I find the error involved in the improved approximation? This is the series I am working with...
  16. Quarlep

    How do scientists estimate the total energy of the universe?

    I posted recently on a banned topic, apologies for that. Under advisement of a mentor I've decided to ask a positive question instead, how do scientists estimate the total energy of the universe?"
  17. V

    Photodiode current estimate in an Infrared Proximity sensor

    I am trying to estimate a current which I can get from the photodiode in a simple proximity sensor application having a IR LED emitter and a photo-diode detector. The LED and the photodiode are mounted in the same plane, on a PCB board, and separated about 10mm. If I have a flat Lambertian...
  18. S

    Estimate stopping force of roof versus tornado

    Problem statement In the not-so distant past, authorities recommended leaving the windows to a house open in a tornado to equalize the pressure and avoid blowing off the roof. We can estimate the validity of the advice. Assume the pressure inside the house is one atmosphere. Approximate...
  19. T

    Estimate number of terms needed for taylor polynomial

    Homework Statement For ln(.8) estimate the number of terms needed in a Taylor polynomial to guarantee an accuracy of 10^-10 using the Taylor inequality theorem. Homework Equations |Rn(x)|<[M(|x-a|)^n+1]/(n+1)! for |x-a|<d. The Attempt at a Solution All I've done so far is take a couple...
  20. Logan Land

    MHB What is the meaning of FWHMP and Q in my lab data?

    During lab I obtained the data in the attached photo. It then asked for me to plot the data and get an estimated FWHMP as well as a "Q" First question is what does FWHMP and Q stand for? Second, where on my graph would I estimate these?
  21. D

    Given z=x²+3xy-2y² Estimate the change in z

    1. Given z=x²+3xy-2y² Estimate the change in z when x changes from 2 to 2,5 and y changes from 3 to 2,52. I am stuck with the math and can't figure it out as what I need to do further.3. a=2 b=3 Δx= +0,5 Δy= -0,5 dz/dx = 2x+3y =2(2)+3(3) =13 dz/dy = 3x-4y =...
  22. A

    Estimate pipe diameter based on flow rate

    I'm designing a testing unit where I need to estimate the smallest diameter of a short complex pipe (around 1 meter, three bends and some diameter viariations). Since the pipe is being cooled down in a water bath after production, my idea is to force water with a known pressure in one end of the...
  23. nomadreid

    To empirically estimate the big-Oh in small programs

    Homework Statement First, I am a teacher preparing to give a discrete mathematics course, in which I will not do any computing, but the students will (in Python). I want them to make empirical estimates for the growth of their (short) recursive programs by putting in some sort of "counter" in...
  24. C

    The cost estimate of rack and pinion used in power steering system

    I'm working on the design project with my partner for mechanical engineering machine design course. We're modeling the rack and pinion used in power steering system. How do you determine the cost estimate for the rack and pinion? Any specific steps we need to follow?
  25. T

    Estimate for root-mean-square uncertainty

    Homework Statement In classical mechanism, the lowest possible energy accessible to any system is the minimum potential energy, in this case 0. However, quantum mechanically, one finds that there is a zero-point energy (where ground state energy > classical minimum). Fundamentally, zero-point...
  26. S

    Estimate the mass of a spinning ice skater

    Homework Statement If you have data such as time of rotation when arms are extended and the lengths of their folded and extended arms measured from the centre of the skater. I know I1ω1=I2ω2 and can work out ω from the radius and time of rotation. Where can I go from here to estimate the mass...
  27. W

    Estimate the standard enthelpy of formation

    Homework Statement The standard enthalpy of formation of the metallocene bis(benzene) chromium was measured in a calorimeter. It was found for the reaction Cr(C_6H_6)_2(s) --> Cr(s) + 2(C_6H_6)(g) that \Delta_r U~at~583 K = +8.0 kJ/mol . Find the corresponding reaction enthalpy and estimate...
  28. D

    MATLAB Matlab estimate PDF from random variable X

    How do I estimate the pdf from a random variable \(X\) where \(X = U_1 - U_2\) and \(U_i\) are uniform random variables? In the code below, I used unifrnd(-5, 5, 1000, 1) which generated a 1000x1 vector of uniform random number between -5 and 5. How do I estimate the PDF for X? rng; X =...
  29. D

    Is Time Dilation Considered in Determining the Age of the Earth?

    I have been watching Cosmos and it is talking about how we determined the age of the Earth from meteors, since it's very difficult finding the oldest pieces of Earth otherwise and these are from the creation of the Solar System. Wikipedia: Estimate of the Earth's Age I think there is still...
  30. G

    How to estimate latent heat of polymorphic phase transitions

    Hello, I know that the latent heat of a first-order isothermal and isobaric phase transition is in general given by the difference in enthalpies between the two phases, but my question is: do you know if there is there a way to estimate its value "from first principles" for the case of a...
  31. B

    MHB How do I decide this total cost and how do I make a minimum estimate?

    Principle: 10K Interest: 10% compounded annually Time: Over five years What is the total cost of all of this factored in? Could I get the formula so I can use it to apply to a real problem?
  32. I

    MHB Estimate $y(0.5)$ using Euler's Method

    use euler's method with step size 0.1 to estimate y(0.5), where y(x) is the solution of the initial-value problem y'=y(x+1), y(0)=1. round your answer to four decimal places. this is all I've done so far $y'=y(x+1)$ $y(0)=1$ $h=0.1$ $x_{0}=0$ $y_{0}=1$ $x_{1}=x_{0}+h=0+0.1=0.1$...
  33. T

    How Should I Determine the Correct Power Rating for a Motor Winding Paper?

    Hello, I'm trying to size a motor for an application that I'm working on. The application involves winding paper with two motors. One motor will unwind and the other motor will rewind. However, I'm trying to figure out what the motor power rating should be. Here's the worst case scenario...
  34. W

    How to estimate 2 points on the unit circle

    I have some noisy data (x-y coordinates) containing two distinct clusters of data. Each cluster is centred at an unknown point on the unit circle. How can I estimate these two points (green points in the diagram)? We can assume the noise is Gaussian and noise power is equal in x and y...
  35. R

    Bayesian point estimate

    Homework Statement Let Y_n be the nth order statistic of a random sample of size n from a distribution with pdf f(x|\theta)=1/\theta from 0 to \theta, zero elsewhere. Take the loss function to be L(\theta, \delta(y))=[\theta-\delta(y_n)]^2. Let \theta be an observed value of the random variable...
  36. U

    Thermal Conductivity - Estimate Temperature

    Homework Statement Given an insulating case outer surface at 25C, radiates heat to surroundings at 20C. Find temperature inner surface. Homework Equations The Attempt at a Solution The heat is conducted through a thickness of 2.5mm, with a temperature difference of 5oC. Thus...
  37. R

    MHB Estimate order O(h)

    Consider non-dimensional differential equation for the height at the highest point is given by \begin{equation} h(\mu)= \frac{1}{\mu}- \frac{1}{\mu^2} log_e(1+\mu) \end{equation} $0<\mu<<1.$ Deduce an estimate to $O(\mu)$ for $h(\mu)$ and compare with $t_h(\mu)=1-\frac{\mu}{2}+...$ => I really...
  38. R

    MHB Using Sampled Data to Estimate Derivatives, Integrals, and Interpolated Values

    I think you may be interested in the Wolfram Demonstration, "Using Sampled Data to Estimate Derivatives, Integrals, and Interpolated Values"
  39. C

    MHB Confidence intervals and point estimate problems

    I am lost on how to do these two problems and can't find info on how to solve them anywhere. If anyone can get me on the right track as to how to start, that would be amazing! 1. A 99% confidence interval for a population mean was reported to be 152 to 158. If the standard deviation is 10...
  40. aboojoo

    How do I estimate hours of use and find power for appliances?

    Homework Statement Please look at the attachment, I'm not sure how to go about figuring out the estimated hours of use per week for the appliances, and the Power(wattage) as well. I figured to find out one you would need the other, they are given in the answers section but I need to know how...
  41. A

    How to estimate transfer function given a transmissibility plot?

    How would I estimate the transfer function for transmissibility given this plot: I am told that the data does not include phase information, but assume that the phase is 0 deg at low frequency and -180 deg at high frequency. I must provide a brief rationale for each component of the transfer...
  42. M

    MHB Estimate the integral of g over the cube

    Hey! :o I have the following exercise: Integrate the $g=xyz$ over the cube that is on the first half-quadrant and it is bounded from the levels $x=1, y=1, z=1$. Having the following formula: $ \int \int_A{g(x,y,z)dS}= \int \int_D {g(x,y,z(x,y)) \sqrt{1+z_x^2+z_y^2}dxdy}$ do I have to take...
  43. E

    Estimate the error variance of Autoregressive model

    Hi everyone, hopefully someone can help For an vector AR(1) model of the form y(t)=Ay(t-1) + et How does one estimate the variance of the white noise input. I was under the impression that one can simply use the residual of the model fit and estimate the variance from this, when I do a...
  44. T

    Estimate energy of infinite well (ground state)

    Homework Statement We have to estimate the ground state energy of an infinite potential well (1d) using an argument based on the Heisenberg uncertainty principal. We then are supposed to compare it with the exact value from the eigenvalue equation. Homework Equations Below The...
  45. MarkFL

    MHB OliverG's Calculus Q: Estimating Pool Volume w/ Trap Rule

    Here is the question: I have posted a link there to this thread so the OP can view my work.
  46. S

    MHB Use midpoint rule to estimate the average velocity?

    Use the midpoint rule to estimate the average velocity of the car during the first 12 seconds. Click here to see the graph from my book. i understand the midpoint rule is \frac{b - a}{n} so \frac{12}{4} = 3 so n = 3 I also know that \frac{1}{12} \int^{12}_{0} v(t)dt But now I'm...
  47. B

    Capacitor question - Estimate the required radius of each plate

    Homework Statement Estimate the required radius of each plate. The plates are separated in air by 0.01mm and has a capacitance of 400pF. There are 4 pairs of plates. Homework Equations c= εrε0*A(n-1)/ d The Attempt at a Solution Find area. Transposing for A A = dc/εrεo A=...
  48. K

    Using sigma sums to estimate the area under a curve

    Homework Statement My apologies in advance for the messiness of the equations; the computers available to us do not correctly process the LaTex code. I am tasked with estimating the area under the curve f(x)=x2+1 on the interval [0,2] using 16 partitions. Online calculators and my...
  49. K

    How Do You Estimate Logarithms Using Basic Logarithmic Properties?

    Homework Statement Given that log(2) is roughly 0.30 and log(∏) is roughly 0.5, estimate the values of log(4), log(5), log(6) and log(8). Homework Equations log(ab)=log(a)+log(b) log(a/b)=log(a)-log(b) log(a^n)=nlog(a) The Attempt at a Solution I found log(4) and log(8) using...
  50. N

    Estimate global temperature increase from solar forcing

    Homework Statement using a climate sensitivity of 0.5K per watt per square meter, estimate how much of the .9 c global temperature increase since 1900 could be due to solar forcing who value is the range of .06 to .24 w/m2 Homework Equations The Attempt at a Solution .5 x .06 =...
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