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. R

    Using Maclaurin's theorem to estimate second derivative

    Homework Statement Use Maclaurin's theorem to estimate d^{2}y/dx^{2} at x=0 It's the deflection of a 2m beam, where x is the distance along the beam, y is the deflection in mm. Homework Equations The Attempt at a Solution I didn't know where to start so I tried to solve it a different...
  2. Z

    Stargazing How to estimate distance by a telescope

    Guys I don't know if people could estimate distance to a target object by looking through a telescope. I believe telescopes for this kind use must be calibrated some how. When the time people sailed in the ocean and when they spotted another boat by the telescope, how did they tell the...
  3. C

    Fermi estimate of the week: Riemann hypothesis

    For those not familiar with the term Fermi estimate/problem/question see here: http://www.vendian.org/envelope/dir0/fermi_questions.html http://en.wikipedia.org/wiki/Fermi_problem My question: Between the time that Riemann posed his famous question (in 1859) and now, how many hours have...
  4. marcus

    Three times as many stars? (new estimate by van Dokkum and Conroy)

    The technical paper (published in Nature): http://arxiv.org/pdf/1009.5992v1 The NYT journalistic account: http://www.nytimes.com/2010/12/02/science/space/02star.html?_r=1&ref=science ==quote== How Many Stars? Three Times as Many as We Thought, Report Says By KENNETH CHANG Published: December...
  5. P

    Estimate f ' (pie/ 4) by using a graphing utility

    Homework Statement Let f (x) = sin x. Estimate f ' (pie/ 4) by using a graphing utility. a) 1 / 4 b) √2 /2 c) 1 / 2 d) pie / 4 The Attempt at a Solution Is it sin (45) = √2 /2. I'm wondering if b is the answer.
  6. R

    Software to estimate n, k Values of a thin film

    Hi! I have samples of multiple thin films. Thin film of which refractive index needs to be estimated is sandwiched between substrate and capping layer of known refractive indices and extinction co-efficients. I have transmission and reflection spectra of the samples and with the help of these...
  7. L

    Estimate the mass of the Coma cluster

    Homework Statement Use the results we derived in class based on the virial theorem to estimate the mass of the Coma cluster of galaxies, which has a radial velocity dispersion of o = 977 km s1 and a radius R = 3 Mpc. You can assume an isothermal sphere model for the mass distribution and...
  8. M

    Estimate the terminal speed of a wooden sphere

    Homework Statement (a) Estimate the terminal speed of a wooden sphere (density 0.870 g/cm3) falling through air, if its radius is 8.50 cm and its drag coefficient is 0.500. (The density of air is 1.20 kg/m3.) (b) From what height would a freely falling object reach this speed in the absence...
  9. P

    Estimate the boiling temperature of HCN at 1 bar.

    Homework Statement The standard molar enthalpy of vaporization for HCN is Δ_vap H = 26.23 kJ mol^−1 vap Estimate the boiling temperature of HCN at 1 bar without using tabulated thermodynamic data. Provide your answer in units of ºC . Homework Equations I figure Trouton's rule would...
  10. L

    Estimate the mass accretion rate

    Homework Statement A typical quasar luminosity is about 1012 L, where L = 3:83 1033 erg s1 is the luminosity of the Sun. If the energy is released by mass falling into a SMBH, estimate the mass accretion rate. (Convenient units are solar masses per year.) B)If the mass accretion rate is...
  11. L

    Estimate the radius of the largest asteroid you could escape by jumping

    Homework Statement estimate the radius of the largest asteroid from which you could escape simply by jumping off. Homework Equations R^2= 3gh/4piGp The Attempt at a Solution Would I use this formula to solve it? Found it online but dose not seem right. this is a 2 part problem...
  12. L

    Estimate the velocity achieved when you jump

    Homework Statement estimate the velocity you achieve when you jump straight up hint use the height you reach jumping on Earth to estimate the change in potential energy and then use conservation of energy to estimate you initial kinetic energyHomework Equations ymax=(v^2 sin^2 @)/2g The...
  13. L

    Dimensional analysis to estimate gas clounds collapse

    Homework Statement stars form by gravitational collapse of interstellar gas clouds. use dimensional analysis to estimate how long it takes for a cloud with a density p=Mo pc^-3 to collapse Mo= 1.9898e33 g Homework Equations The Attempt at a Solution I just have no idea how to use...
  14. S

    Electric cable in a Vertical Tube: Estimate the Conductor Temperature

    Hello, I have an electric cable in a vertical steel Tube. I estimated the temperature that will reach the JTube exposed to sun radiation. I came with these equations QCable+ Qsun - Qradiated = mc( Tfinal - TAmbient) where QRadiated= k.A.(Tfinal^4-TAmbient^4), QSun=234 [W/m^2] * A...
  15. H

    Estimate the radius of a solar mass black hole.

    Estimate the radius of a solar mass (2 × 1030 kg) black hole. How do I do it? I have literally no idea! Thanks in advance for any help.
  16. B

    Calculus Problem, Estimate h'(-1)

    Homework Statement A function f with domain [-5, 5] has a derivative f' whose graph is shown http://img718.imageshack.us/img718/2842/calcpic.jpg" . Also, f(-1) = 2. a) If h(x) = ef(x), estimate h'(-1). 2. The attempt at a solution a) h'(x) = f'(x)ef(x) h'(-1) = f'(-1)ef(-1)...
  17. J

    Counting Seconds to Estimate Storm Distance

    We got some cool weather today along with some scattered showers. My wife was sitting there in deep concentration so I asked her what she was thinking. She said she was counting the seconds between the lighting flash and the thunder. She said that the light gets here much faster than the sound...
  18. D

    Estimate relative error using differentials

    Area of right triangle with hypotenuse H is A=(1/4)H^2sin(2theta) where theta is one of the acute angles. Use differentials to estimate the relative errors of the area A if H=4cm and theta is measured to be 30 degrees with an error of measurement of 15 minutes of arc. note: a minute...
  19. N

    Essentials of Calculus use a calculator to estimate any extrema

    Homework Statement Use a calculator to estimate any extrema of this function: f(x)=5x^3-30x^2+45x+5(sqrt(x)) Homework Equations The Attempt at a Solution I don't know how to find it using a calculator. f'(x)= 15x^2-60x+45+(5/2)x^(-1/2)
  20. S

    How to estimate the Startup torque of a pump motor

    Hi Guys, I have a problem about the starting current of a pump's electrical motor. I have the working condition of the pump (torque, power, speed, P and Q) But how could I calculate the start up current of an IEC standard motor? Seems I has to gather a Torque-speed curve from the...
  21. L

    How do I use t-distribution to estimate the tα/2

    Hi, I need help understanding how do I use t-distribution to estimate the tα/2 . Also what is meant when it asks "verify your result with empirical rule"
  22. K

    Road construction method and estimate

    [b]1. we have 1 road length 10km x 8m is given to do for 6 months. the works was given a volume of Embankment 80,000m3 and the volume of subase 24000m3 and the volume of base course 16000m3. so what can we do to make the road and estimate the cost and describe the work of tool to use. (just...
  23. M

    Estimate the overall change of entropy for this system.

    Homework Statement A piece of metal at 80°C is placed into 1.2 litres of water at 72°C. This thermally isolated system reaches a final temperature of 76°C. Estimate the overall change of entropy for this system. Homework Equations (delta)S = Q/T The Attempt at a Solution...
  24. russ_watters

    Gulf Oil Spill Velocimetry-Based Flow Rate Estimate

    In the thread in P&WA on the issue of the oil spill, I expressed my skepticism that the rate of the spill could be accurately measured via analysis of underwater video clips. That skepticism was strengthened by the recent statement by Prof Steven Wereley, the originator of the first such...
  25. M

    Prove Limit of Integral Estimate: Zero

    Homework Statement I have to prove that the solution of an ODE can be continued to a function \in \mathcal{C}^1(\mathbb{R}) . The solution is: e^{-\frac{1}{x^2}} \int_{x_0}^x -\frac{2e^{\frac{1}{t^2}}}{t^2} dt It is clear that this function is not defined in x=0 . Its limit for x \rightarrow...
  26. I

    Estimate the energy difference

    Homework Statement Two parts to this one: (a) If the 1s^2 ^1S ground state and 1s2s ^1S excited state of He has an energy separation of, estimate the energy difference between the same two states for Ne^{8+}. (b) The 1s2s ^1S and 1s2s ^3S states of He have an energy separation of 0.8...
  27. W

    How to estimate the behavior of a solution of a differential equation at \infty?

    i have a first order nonlinear differential equation y'=-sin^2(kx+y)/kx the boundary condition is y(x=0)=0 here k is a real positive number i want to estimate the behavior of y as x goes to infinity how to do this? any book for reference?
  28. M

    Estimating Bandwidth for a Low-Pass Filter Using Real and Complex Numbers

    Hi, this is a problem I am trying to do: So I found that at 3dB, V0=0.7079Vi and I wasn't sure if I should use real numbers or complex numbers, I did both, I'll show the real one: Vo/Vi=0.7079=R/(R+1/wc)=Rwc/(Rwc+1)...I can solve for w, but this will only give one answer, when I use complex...
  29. H

    Lagrange error bound to estimate sin4° to five decimal places( maclaurin series)

    Homework Statement Estimate sin4 accurate to five decimal places (using maclaurin series of sin) Homework Equations The Attempt at a Solution Lagrange error bound to estimate sin4° to five decimal places( maclaurin series) 4°=pi/45 radians |Rn(pi/45)<1*(pi/45)^n+1/(n+1)...
  30. R

    Number of degrees of freedom in the sigma estimate

    Homework Statement I have estimated the standard deviation of the population of my samples from the standard deviations from each of the samples with the equation found below. And I am to construct a confidence interval for a contrast, thus I will need the number of degrees of freedom for which...
  31. R

    Estimate amount of possums in the park

    1. Urula is doing a project and has caughed, tagged and released 50 possums. Estimate the population of the possums in the park. Three nights later she captures a sample. 2. If ursula captures 20 possums and 4 of them are tagged, what would her estimate of the local possum population be...
  32. Z

    Young's Modulus - estimate elastic limit

    Homework Statement I'm completing a homework for Young's Modulus and one question asks to estimate the elastic limit for the wire which was used. I can see where this approximately is on the graph I have drawn. When the question asks to estimate the elastic limit, does this mean to...
  33. V

    Velocity final estimate on frictionless craft

    Homework Statement I am trying to calculate the estimated final velocity of a R/C hovercraft i am trying to built. The craft's weight is 6lbs and it is powered by a electric ducted fan that produces 21.3 ounces of thrust. Assuming this craft is actually hovering (no friction with the ground)...
  34. R

    Estimate its capacitance to earth

    Homework Statement A telephone wire of diameter 1mm is suspended 10m above the ground. Estimate its capacitance to Earth per unit length Homework Equations The Attempt at a Solution I've tried to solve the problem by using the formula for a cylindrical capacitor and got the answer...
  35. sophiecentaur

    How did Victorians estimate the ages of fossils?

    They didn't have Carbon 14 and I think fossil tree rings (dendochronology?) is a modern method so where did they get their millions of year from?
  36. S

    Cost estimate of Hydrogen Fuel Cells versus Gasoline

    Although a complete cost analysis is much more complicated, the particular question only requires the following: an energy cost estimate (in terms of $/Joule). This was directed to be done by taking volumetric or mass based costs of each fuel as well as the associated energy conent or energy...
  37. S

    Estimate ground state energy with HU

    Hi, i worked through several examples where the ground state energy of a particle in an arbitrary potential V(r) is estimated with Heisenberg's uncertainty relation. In these examples they prepare the Hamiltonian for the particle. For example the Hamiltonian for a particle in a harmonic...
  38. O

    How to estimate the Rating of Transformer

    T/F=Transformer usually T/F is used according to the load of the area, street etc. How they estimate that 50 KVA transformer is enough for this load,street? any formula or method please explain ::Thanks
  39. T

    Monte Carlo Integration: Error Estimate Reliability for Non-Square Integrables

    Hi! I need help with the monte carlo integration: reliability of the error estimate for functions that are not square integrable. I'm supposed to investigate this topic.*Hence my first question is what is a function that is not square integrable? I found that such a function is 1/sqrt(x) on...
  40. X

    The Alternating Series Error Estimate

    summation from 1 to infinite: (5n)/(n^2+1) What is the maximum amount of error of s4 as compared to the infinite series? error=S-Sn<bn+1 I got S4=-14/17 and S5=-25/26 but how you suppose to get S? i though you can't tell what a alternating series converge to
  41. A

    Nonlinear Lifting Line method to estimate wing lift distribution

    Hi all, I have implemented a nonlinear lifting line method to estimate lift/induced drag of a typical wing. This method utilizes 2D lift coefficient data, and uses a numerical technique to solve the nonlinear equations. The program I have written in MATLAB is working, though I would like to...
  42. N

    Using an expanded power series to estimate

    Homework Statement (a) Expand f(x) as a power series f(x)=\frac{7}_{\sqrt[4]{1+\frac{x}_{14}}} Which I converted to... 7 - \frac{1}{8}*x + \sum^{\infty}_{n=2}7*(-1)^{n}*\frac{1*5*9*...*(4n-3)}{4^{n}*n!}*(\frac{x}{14})^{n} (b) Use part (a) to estimate 7 / (1.1)^(1/4) correct to...
  43. B

    Accuracy of generation time estimate

    Homework Statement How accurate is the estimate for (cohort) generation time (the type you'd have on a life table)? Homework Equations Cohort generation time: Tc = Sum of (x*Fx)/sum of Fx The Attempt at a Solution Tc = 2.77 (for 7 generations) So the generation starts of with...
  44. W

    Can AA Batteries Store Enough Energy for Wireless Sensor Networks?

    Hi all, I'm using NS2 to simulate wireless sensor networks. I want an estimate of the initial sensor battery energy. I know that each sensor node uses 2 AA batteries. I have no assumptions about the current. I search for a while on the internet but couldn't find a direct estimate. Thanks...
  45. T

    Using differentials to estimate the amount of tin

    Homework Statement Use differentials to estimate the amount of tin in a closed tin can with diameter 8cm, and height 12cm, if the tin is 0.04 cm thick. The way I did this was to subtract the Max volume by the Enclosed volume. Max Volume is pi(4)(12) Enclosed Volume is pi ( 8 - 2(0.04) )/2...
  46. D

    How can you estimate mass of star?

    Is there a way to estimate the mass of a star using Spectral Class and absolute magnitude? If you can't then what info do I need in order to so. Thanks, Dan
  47. E

    What is the current best estimate for LHC online

    at design energies 14TEV collisions?
  48. K

    Can Probability Estimation Tools Enhance Scientific Research?

    i need this information..please someone help me! What useful tool allows us to refine?
  49. H

    Estimate the average force exerted by a shot-putter

    Homework Statement Estimate the average force exerted by a shot-putter on a 7.5 kg shot if the shot is moved through a distance of 3.0 m and is released with a speed of 11 m/s. Homework Equations F=ma using cos and sin? The Attempt at a Solution not sure how to begin
  50. C

    Fermi Estimate with atmospheric pressure

    1. There are many different definitions of the location of the top of the atmosphere – the near edge of outer space. • Until around 1600, it was believed that the Earth’s atmosphere extended throughout space (recall that the Earth was also considered to be the center of the Universe until...
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