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. billyray

    Estimate primary line coeffiecients

    Homework Statement Figure shows a 50 Hz, high-voltage, transmission line. The relationships between the sending and receiving end voltages and currents are given by the complex ABCD equations: where 'S' stands for sending-end and 'R' stands for receiving-end (a) Given the parameter...
  2. K

    Unbiased estimate of a parameter in the Rice distribution

    I am trying to estimate the amplitude of a real signal with a particular frequency and unknown phase. The signal is sampled at a frequency much higher than the Nyquist frequency for the signal. For simplicity, I take an FFT period which is a multiple of the signal period (which conveniently is a...
  3. T

    Heat Transfer & Combustion: Estimate Pipe Heat Loss/m

    << Mentor Note -- poster reminded to use the standard Template >> Question Three A pipe of outside diameter 200 mm is lagged with an insulating material of thermal conductivity 0.06 W m-1 K-1 and thickness 75 mm. The pipe carries a process fluid at a temperature of 300 °C and the average...
  4. T

    Other Book recommendations for making guesses, estimates, inferences

    I came across this book 'Street fighting Mathematics, The art of educated guessing and opportunistic problem solving' , by Sanjoy Mahaan, published by MIT press. The book talks about how we can guess some property of the solutions of a number of physics and math problems without actually solving...
  5. Kara386

    Roughly estimate the probability that 2 photons are from Higgs

    Homework Statement Make a very rough estimate of the probability that two high energy photons with an invariant mass of 126GeV are decay products of the Higgs. Use information found elsewhere (so I need to find this info preferably on the internet). Homework EquationsThe Attempt at a Solution...
  6. B

    MHB Using differentials to estimate error

    one side of a right triangle is known to be 12 cm long and the opposite angle is measured as 30°, with a possible error of ±1°. (a) Use differentials to estimate the error in computing the length of the hypotenuse.
  7. Noisy Rhysling

    Do we have a good estimate for the damage the Yellowstone....

    ..."supervolcano" will cause? Immediate area affected, ash patterns, etc?
  8. R

    Estimate average speed of electrons in gas?

    Homework Statement Suppose that a heated gas comprised of electrons glows bright orange when it is in use. Estimate the average speed of the electrons in the gas. Model this gas as an ideal gas. Homework Equations None. I have no clue. This is a "review" question on a chapter titled "Current...
  9. S

    I Possible to estimate the location of a measurement point?

    Hi guys, I am just wondering if it is possible to calculate/estimate the location of measurement point on a rigid body? For example, let's say we have a rigid body that is in motion. We attach a sensor, say an accelerometer on the surface of the rigid body. Now can we estimate the location of...
  10. electr

    Estimate the local heat transfer flux

    Homework Statement Liquid ammonia is heated as it flows at a mean velocity of 2 m s–1 through a circular pipe. The pipe, which has an internal diameter of 75 mm, is at a uniform temperature of 27°C, and the ammonia at a section 1.2 m from the inlet to the pipe has a temperature of –23°C. Use...
  11. mesa

    What is the estimated cost of nuclear fusion research since its inception?

    Hey guys, Do you have ideas on the current dollar amount spent on nuclear fusion research since it's Rutherfordian inception?
  12. bananabandana

    Estimate of time of the universe

    Homework Statement Show that the time of matter-radiation equality, t_{eq} can be written: $$ t_{eq} =\frac{a_{eq}^{\frac{3}{2}}}{H_{0}\sqrt{\Omega_{m}}} \int_{0}^{1} \frac{x}{\sqrt{x+1}} dx $$ Homework Equations $$ t = \int_{0}^{t} dt = \int_{0}^{a} \frac{1}{H(a)} \frac{da}{a} $$ [Given]...
  13. A

    How to estimate a spring-mass-damper system's damping ratio?

    I have constructed a torsional balance, which basically consists of a torsional spring, and a damper. I model this as a spring mass damper system. And it is used to measure thrust of some propulsion system. This is how the system looks like. I am just very eager to find out, how to model the...
  14. J

    Velocity Estimate from Schlieren Flow Visualization

    Hi, I recently came across a blog on schlieren visualization (http://ottobelden.blogspot.in/2010/07/homemade-schlieren-photography-setup.html). I replicated it with the following: Convex lens (130 mm dia and 350 mm focal length), LED light source (5 mm white LED) and smartphone camera (Moto G4...
  15. FritoTaco

    Estimate Instantaneous Velocity

    Homework Statement If a ball is thrown into the air with a velocity of 48 ft/s, its height in feet t seconds later is given by y = 48t − 16t2. (a) Find the average velocity for the time period beginning when t = 2 and lasting for each of the following. (i) 0.5 seconds (ii) 0.1 seconds...
  16. N

    Estimate the pressure exerted on a floor

    Homework Statement 3. (I) Estimate the pressure exerted on a floor by (a) one pointed chair leg (66 kg on all four legs) of 2 area  0.020 cm , and (b) a 1300-kg elephant standing on one foot   2 area  800 cm . Homework Equations P=F/A=W/A The Attempt at a Solution I know the solution...
  17. R

    I Estimate the number of CMB photons in 0.25-litre

    i know that the total energy density of a blackbody radiation is E= 4 segma/C * T^4 so how i can use this to find the number of the CMB photons in 0.25 litre?
  18. O

    Estimate the radiation pressure

    Homework Statement a) Estimate the radiation pressure due to a 100 W bulb at a distance of .08 m from the center of the bulb. b) Estimate the force exerted on your fingertip if you place it at this point. (Assume an area of .0001 m2 for the fingertip.) Homework Equations F=PradA The Attempt...
  19. maxhersch

    Estimate Vector Field Surface Integral

    I assume this is a simple summation of the normal components of the vector fields at the given points multiplied by dA which in this case would be 1/4. This is not being accepted as the correct answer. Not sure where I am going wrong. My textbook doesn't discuss estimating surface integrals...
  20. evinda

    MHB How can we improve the estimate?

    Hello! (Wave) Let $u(x)$ be a solution of the problem $$Lu=-1 \text{ in } \Omega , u|_{\partial{\Omega}}=2, (c(x) \leq 0)$$ I want to determine the constants $c_1,c_2$ such that $c_1 \leq u(x) \leq c_2 (1)$. Also I want to improve the estimate $(1)$ when it is furthermore given that $c(x)...
  21. P

    Estimate the E-field required to ionize Hydrogen

    Homework Statement Estimate the E-field required to ionize Hydrogen in a time comparable to the time taken for the electron to orbit the nucleus. (n=1 ground state) (hint: relate the required E field to the energy of a charged particle) Homework Equations F = mv^2/r (rotational) F = Ze^2/Kr^2...
  22. A

    How Accurate Are Stopwatch Measurements in Physics Experiments?

    Homework Statement Question: A student used a digital stopwatch three time 10 oscillations of a pendulum. The timings were 13.52s, 13.64s and 13.58s a) Calculate i the average time for 10 oscillations, ii the time period of the oscillations. b) Estimate the accuracy of the timings, giving a...
  23. L

    I Chernobyl Dose Model & Estimates

    Hello all, I've been tasked with developing a model for dose received from the Chernobyl Accident. I'm struggling a little to find dose estimates from which I can extrapolate back to find the initial dose received. Does anyone have any references that they can point me towards? I believe there...
  24. M

    MHB Estimate the cost for tyres using the mean

    Data Data obtained from a survey conducted by a tyre manufacturing company, using a sample of 60 tyres of a certain category, on the distance tyres ran before they became unsuitable for further use. Problem i. What is the modal class ii. Taking the mid value of the modal class as the...
  25. H

    Estimate the total harmonic distortion present

    The supply current was sampled 1024 times over a very short time interval. The data so obtained is given in column B of the accompanying Excel worksheet1. This worksheet has been set up to give a graph showing the spectral components of the data. Question 3 i) Obtain the Fourier Transform for...
  26. Jeffack

    I Hessian of least squares estimate behaving strangely

    I am doing a nonlinear least squares estimation on a function of 14 variables (meaning that, to estimate ##y=f(x)##, I minimize ##\Sigma_i(y_i-(\hat x_i))^2## ). I do this using the quasi-Newton algorithm in MATLAB. This also gives the Hessian (matrix of second derivatives) at the minimizing...
  27. Safinaz

    I How to estimate this cross section

    Hi all, Do any has an idea how to give a rough estimation for this process's cross section: g g -> H -> h h, (h -> b b~), ( h -> b b~) ? where h is SM Higgs and H is a heavy Higgs boson with BR (H > hh) ~ Gamma (H > hh) ~ 10^-3 GeV and sigma (g g > H ) ~ 10 pb .. When I calculated it by...
  28. S

    Least square estimate problem

    Homework Statement Suppose that ##Y \sim N_n\left(X\beta,\sigma^2I\right)##, where the density function of ##Y## is $$\frac{1}{\left(2\pi\sigma^2\right)^{\frac{n}{2}}}e^{-\frac{1}{2\sigma^2}(Y-X\beta)^T(Y-X\beta)},$$ and ##X## is an ##n\times p## matrix of rank ##p##. Let ##\hat{\beta}## be the...
  29. A

    MHB Margin of error and point estimate together

    Hey all I have one last question for you. I just need clarification on point estimate and margin of error as I have to find both in a problem. Let's say the endpoints are 5.9 and 8.1. When I do a margin of error problem, I subtract the mean of 7 from 8.1 right? When I do point estimate do I add...
  30. S

    Estimate vibrational frequency of N2 molecule

    Homework Statement Experimental data for the heat capacity of N2 as a function of temperature are provided. Estimate the frequency of vibration of the N2 molecule. Homework Equations Energy of harmonic oscillator = (n+1/2)ħω C=7/2kB Average molecular energy = C*T But this is an expression...
  31. Alfreds9

    Is it possible to estimate a light source wattage remotely?

    I'd like to know if it's possible to roughly estimate a light source wattage remotely, knowing the distance and perhaps estimating that at such a distance it's still above the minimum human recognizable threshold at night (in a light polluted area). Maybe using a DSLR camera could help by...
  32. henrco

    Estimate gravitational energy from supernova

    Homework Statement Suppose that a 15 M(solar masses) star finally runs out of nuclear fuel in its core and undergoes a Type II supernova explosion. You are going to analyse the energy budget, calculating all the quantities in Joules. a) Estimate the amount of gravitational energy that would be...
  33. whatphysics

    Using differentials to estimate the maximum possible error

    Homework Statement Consider a closed rectangular box with a square base of side 3cm and height 5cm. If the side is measured with an error at most 0.02cm and the height is measured with an error at most 0.01cm, use differentials to estimate the maximum possible error in computing the volume of...
  34. S

    Estimate the uncertainty in electron's position.

    1. Question The speed of an electron is known to be between 6.0×10^6 m/s and 6.7×10^6 m/s . Estimate the uncertainty in its position. Homework Equations ΔpΔx ≥ h/2π (mΔv) Δx ≥ h/2π (Since Δp= mΔv) Δx≥ h/2π(mΔv) h= 6.63*10-34 J*s c= 3.0*108 mass of electron= 9.11*10-31 The Attempt at a...
  35. P

    Estimate time scale of expansion of a star

    Homework Statement A star experiences a sudden increase in pressure to a new value P'. Taking the average density as ρ and the radius R, estimate the time scale of expansion of the star. (Ignore gravity altogether). Homework Equations The only thing I can see in my notes that may (or may not)...
  36. M

    How do I estimate stress in a non-prismatic shape?

    Homework Statement In a mathematics-based investigation, I am trying to estimate the stress through a voussoir (member) of an arch bridge. However, these members have non-uniform cross-sections. I don't need to know how to exactly calculate the stress in each part of the member, only the total...
  37. A

    Estimating Vapor Pressure of Mercury at 25°C Using Appendix D Data

    Homework Statement Estimate the vapor pressure of mercury at 25 ∘C (use data from Appendix D from the textbook). Homework Equations Using the appendix I can find ΔG, ΔH, and ΔS. The Attempt at a Solution I have no idea where to start. I think that maybe vapor pressure would be found when...
  38. JK423

    How did LIGO estimate the distance of the black holes?

    As we all know, the LIGO collaboration published a paper recently on the first direct observation of a binary merging black hole system. From the observed signal, they were able to infer the black holes' masses and their distance from Earth. However, the fact that they can estimate masses and...
  39. Neeps

    Sailboat rudder physics, and water flow estimate

    Hi. I'm a computer science student developing a kalman filter for autonomous sailboat, but I severely lack knowledge of the physics behind sailboats. I have a wind sensor giving data about wind speed and wind velocity, problem is the data is unreliable. So i thought that i could estimate what...
  40. N

    Using Partial Derivatives to estimate error

    Homework Statement [/B] The area of a triangle is (1/2)absin(c) where a and b are the lengths of the two sides of the triangle and c is the angle between. In surveying some land, a, b, and c are measured to be 150ft, 200ft, and 60 degrees. By how much could your area calculation be in error if...
  41. C

    Estimate top quark branching ratios without calculating

    Homework Statement Hi, I need to get an estimate of the branching ratios of the processes [/B] t ---> b + W ---> b + c anti-s t ---> b + W ---> b + anti-tau nu(tau) without doing the calculations, just a qualitative estimation. I know I have to take into account the way W decays...
  42. H

    How do I estimate how tall this building is?

    How do I estimate the height of the tall building spiderman swings to at 0:48? I need it for a physics assignment. What does you're intuition tell you? (I've never lived in a city full of buildings). Is there a way to estimate it using physics? I'm not sure that building actually exists.
  43. S

    Can a Minn Kota trolling motor be used as an electric generator?

    I am trying to figure out whether I can use a small Minn Kota trolling motor as an electric generator. If I add a 10" prop the max energy from the water passing the prop should be about 700W and if the prop is 50% efficient, it should put half of that on the shaft. I expect the prop to turn...
  44. bcrowell

    Order-of magnitude estimate fails for angular momentum in decay

    When a nucleus gamma decays, the gamma has its intrinsic spin of ##1\hbar##, but it can also carry away a significant amount of angular momentum in addition to that. Quadrupole radiation is very common, and in exceptional cases you can even get gammas with 5 or ##10\hbar##. Now suppose I do the...
  45. A

    Estimate the mean number of decays

    Homework Statement I am given a table of ~3000 measurements for the number of decays from some radioactive substance within some period T. I want to estimate the mean number of decays per period. Homework Equations Poisson distribution How to calculate mean. The Attempt at a Solution My...
  46. S

    Estimating the Age of the Earth Using Uranium Decay

    Homework Statement The half life of U-238 is approximately 4.4 billion years, while U-235 is approximately 700,000,000. A Uranium ore has 0.75% U-235. Assuming there was an even amount of both types of Uranium when the Earth was formed, estimate the age of the Earth. Homework Equations N =...
  47. J

    Estimate diffraction angle - homemade spectrometer

    Homework Statement Estimate the diffraction angle. The spectrometer is made from rolling up a 30cm long piece of cardboard into a tube. Duct tape is placed over one end, and a thin slit is made. The other end has a diffraction grating held in place. I look through the diffraction grating and...
  48. P

    How do scientists estimate drug dosage based on studies?

    Scientists usually conduct a variety of in vitro and in vivo studies on rodent and their cell cultures and they show the concentration of a particular drug is effective against the disorder for both in vitro and in vivo for the rodents. My question is how do they translate that to a dose for the...
  49. C

    MHB Using Reimann sum to estimate the value of a double integral

    If R = [−3, 1] × [−2, 0], Use a Riemann sum with m = 4, n = 2 to estimate the value of ∫∫R(y2 − 2x2) dA. Take the sample points to be the upper left corners of the squares. So far, I found the indefinite integral of the function to be y3/3 - 2x3/3 Not sure where to go from here
  50. S

    String Theory: Compactification Estimate Update

    A lot of people quote 10^ 500 as the number of different ways of compactifying the extra dimension in string theory. But I recall somoene saying at a talk that its now much larger than that. What's the current estimate?
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