Data Definition and 998 Threads

Data are units of information, often numeric, that are collected through observation. In a more technical sense, data are a set of values of qualitative or quantitative variables about one or more persons or objects, while a datum (singular of data) is a single value of a single variable.Although the terms "data" and "information" are often used interchangeably, these terms have distinct meanings. In some popular publications, data are sometimes said to be transformed into information when they are viewed in context or in post-analysis. However, in academic treatments of the subject data are simply units of information. Data are used in scientific research, businesses management (e.g., sales data, revenue, profits, stock price), finance, governance (e.g., crime rates, unemployment rates, literacy rates), and in virtually every other form of human organizational activity (e.g., censuses of the number of homeless people by non-profit organizations).
Data are measured, collected and reported, and analyzed, and from data visualizations such as graphs, tables or images are produced. Data as a general concept refers to the fact that some existing information or knowledge is represented or coded in some form suitable for better usage or processing. Raw data ("unprocessed data") is a collection of numbers or characters before it has been "cleaned" and corrected by researchers. Raw data needs to be corrected to remove outliers or obvious instrument or data entry errors (e.g., a thermometer reading from an outdoor Arctic location recording a tropical temperature). Data processing commonly occurs by stages, and the "processed data" from one stage may be considered the "raw data" of the next stage. Field data is raw data that is collected in an uncontrolled "in situ" environment. Experimental data is data that is generated within the context of a scientific investigation by observation and recording.
Data has been described as the new oil of the digital economy.

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  1. N

    Propagating Uncertainty for sets of data?

    I'm writing the paper on this experiment I just did. Basically I took sets of data for two variables (x,y) and I fit the points to a line in Origin to extract the value that I was trying to measure (J). *Using generic variables here* I found a value for J where J = [8*∏*x*a(b+c)] / y I...
  2. M

    Statistics - What should I conclude about this data?

    Hi, This is not really a homework question. Attached is a slide from a statistics presentation I found on the web. I am not sure what conclusion I can draw from this data if I ignore the outlier (1906). Saying "higher magnitude earthquakes result in fewer deaths" seems totally...
  3. Y

    MATLAB Plotting normal modes in Matlab from data in Patran

    Hi, Could You help me with problem mentioned in the topic? I copied translational data (3 column vectors) from modal analysis in Patran (from f06 file). Now I have problem in reproducing the results in Matlab. I am trying to draw normal modes in Matlab, but I haven't got much luck so far...
  4. U

    Biological neuron models and simulated data

    I have some very simple questions. 1. What are the real life applications of the biological neuron models (for example Hodgkin-Huxely model)? 2. Is their any online database from where I can get the original recordings data of a neuron? 3. or is there any way that I can...
  5. T

    Help finding velocity using data table

    Homework Statement Using the data found, in this chart, create a time-velocity data table. Time(s),Position(m)[down]: (0,0), (0.25,0.29), (0.50,1.15) Homework Equations v= change in position/change in time The Attempt at a Solution I'm just wondering which sets of data...
  6. R

    Combining loosely correlated data set

    I need some help finding an appropriate statistics model for some experimental data. Thanks in advance for any suggestions. I am trying to compare simulated results from a code that models nuclide concentrations in spent nuclear fuel to experimental data. These concentrations have...
  7. M

    I have a question about normalization of data

    Hello, please help me with this problem. The question is in the picture (LOOK AT THE ATTACHMENT). I don't know how to normzalize the data. How to know which method should be used? I need two methods of normalization here. HELP! Please teach me in detail. You don't have to give me the...
  8. C

    Best way to visualise data outputted from a C program

    Homework Statement I've written some C code that models the motion of two masses attached to a wall (and each other) by springs like this. The output file is 5 columns; the time, and the positions and velocities of each block at that time. I'm not sure how to visualise my data...
  9. A

    MHB Data Normalization Methods: Understanding and Choosing the Right One

    Hello, please help me with this problem. The question is in the picture. I don't know how to normzalize the data. How to know which method should be used? I need two methods of normalization here. HELP! Please teach me in detail.
  10. E

    How to compare two data sets with statistics?

    I have two questions: I have a set of data, a measured spectrum. When I model the spectrum with a function, I calculate r2=1-(\sum(y-ymodel)2/\sum(y-yavg)2). Q1) However, I have reference data now, which is what the spectrum should be. So is it right to use the same calculation on it for...
  11. S

    Calculating rate constant from a set of data?

    Homework Statement For a reaction, A + H2O --> B + C We're given that d[A]/dt = k[A]n[H3O+]m And also a table of [A] vs time at T1 and pH 1, pH 2; as well as [A] vs time at T2 and the same pH 1 and 2. From this data, we're to find pseudo-n-order rate constants, and then n itself. Next...
  12. S

    Interpreting a graph of lab data.

    So, I've obtained a graph of lab data an it's a plot of thermal resistance versus pressure. Pressure on the x and thermal resistance on the y. If I plot all the points, there doesn't seem to be any trend. The y values are just as likely to decrease as they are to increase with increasing x...
  13. karush

    MHB What is the smallest time from the data given

    https://www.physicsforums.com/attachments/1729 before I proceed with b, c, and d. what really is meant by the smallest time. does this mean the time of one cycle. there are multiple answers if it calculated for t. the steps I used give one but that may not be the correct process. no ans given
  14. M

    Method for checking if digital data is transmitted accurately?

    In this experiment, we recorded a person saying "Aaaaaaa" on the mic as the analog source. And then the analog data was converted into digital data so that the programme in the PC could read it and then the digital data was converted into Analog again to reproduce the recorded voice. I attached...
  15. W

    Interpretation of cyclotron resonance data

    Homework Statement Compare the cyclotron resonance signal from Silicon in figure 28.9b (in Ashcroft and Mermin) with the geometry of the conduction band ellipsoids shown in figure 28.5, and explain why there are only two electron peaks although there are six pockets of electrons. Homework...
  16. T

    Calculating a covariance matrix with missing data

    Consider a co-variance matrix A such that each element ai,j = E(Xi Xj) - E(Xi) E(Xj) where Xi,Xj are random variables. Consider the case that each variable X has a different sample size. Let's say that Xi contains the elements xi,1, …, xi,N, and Xj contains the elements xj,1, ..., xj,n where...
  17. H

    Can Quantum Foam Really be Used for Data Storage?

    I need help as my 17 year old daughter is beating me. A few months ago my wife, daughter and started a competition to see who could get a book published first. My wife has her Master's in education and my daughter is a 4.0 AP high school senior. I have a BSBA from an online degree mill. So I...
  18. Z

    One dimensional transducer data

    I posted this in Introductory Physics but not sure if that was right so I have posted here as well hope that's ok. Homework Statement To run a one dimensional transducer modelling program and analyse the data. The attempt at a solution I have ran the modelling program for different...
  19. Z

    One dimensional transducer data

    Homework Statement To run a one dimensional transducer modelling program and analyse the data. The Attempt at a Solution I have ran the modelling program for different scenarios, first the transducer itself, then with a layer of water on one side, then with a matching layer between the...
  20. Superposed_Cat

    MATLAB MATLAB-Plot two sets of data on the same graph with custom increments

    Hi, I was trying to plot two sets of data on the same graph and this was my solution but this generates a graph with the x-axis in 0.5 increments where I wanted 1. How do I plot two sets of data on the same graph and customize the increments. Thanks in advance. Also, how would I make MATLAB...
  21. B

    How to Program Data Retrieval from Sensors for Beginners?

    How do you get started learning how to write a program to display and manipulate information from various sensors? What I am mainly interested in are volts and mA's since that's what most transducers and sensors use. I would like to be able to see the information on a computer or eventually on...
  22. I

    Visualizing Data in Linux: Recommendations Needed

    Hi to all! I need your opinion about something simple. All we know that in research "industry", in order to visualize their results, they extensively use originLab. Someone told me that "if you want to be called a researcher, then you have to learn origin...". Ok, fine. But I am a Linux...
  23. M

    Where Can I Find Texas Tower Data for Physics Experiments?

    I'd like to produce a plot that looks like Taken from page 86 of AP French's Vibrations and Waves. I'm searching for some good Texas Tower data. Can you recommend an archive of physics experimental data? Or what I'd like even more is a spreadsheet with some texas tower data.
  24. J

    How to Smoothly Distribute Monthly Data Values Across Daily Intervals?

    Hi! I have a problem to resolve this question : I have a total value each month : January = 60 Fébruary = 80 March = 130 April = 150 May = 180 June = 200 July = 210 August = 170 September = 140 October = 90 November = 60 December = 50 I want to calculate the value each day of...
  25. M

    Deriving conclusion from a small data set

    Hi Please see table below GDP growth rates of a group 5 countries. I am trying to derive some conclusions from this small sample. 1. can I conclude that countries in the group have very similar growth rates and there is no significant difference between their growth rates? 2. As...
  26. A

    Computer networks Data communication assignment help please

    Homework Statement I have an assignment for Data communication module but the assignment is based on networking. we were given two tables, which we have to fill in. table no -1 is https://www.dropbox.com/s/2mo4faeuau9mw6m/Screen%20Shot%202013-10-31%20at%2018.54.09.png Homework Equations The...
  27. R

    MHB Theory and Techniques of Data Assimilation

    Suppose we have a dynamical system for a vector x = (u,v,p)^T where u,v,p are scalar quantities. Let the dynamical system be represented by the equations u_(k+1) = u_k +v_k +2p_k v_(k+1) = 2u_k +v_k +2p_k...
  28. R

    MHB Theory and Techniques of Data Assimilation

    Suppose that we wish to estimate the true temperature in a room T_t from an unbiased background estimate T_b and an unbiased observation T_o with error variances σ^2_b and σ^2_o respectively. Suppose further that the background and observation errors are correlated, with covariance ρ. We seek an...
  29. M

    Write an equation based on data

    Hi, I am trying to understand what is the best way to solve problems like the one below. I have a few data points and I need to which function best describes that data. (x, y) = (-3, -32) (-2, 16) (-1, 8) (0,4) (1,2) (2, 1) note that the y parameter in the first data point is -32 and...
  30. C

    How to find Resonance frequency of rectangualr cavity from FDTD data

    Hello, I have written 3D FDTD code with Mur ABC which gives correct results for time domain data. Now I want to compute the resonance frequency of a rectangular cavity using this 3D FDTD code. I don't know how I will do that. Would someone please advise me the steps I need to follow now to...
  31. R

    Find Function to fit data - Card shuffle

    Hello, I had a chat with a person at work and we were discussing a card shuffle and what governed its behaviour. Here's the shuffle rules. Have to use an even number of cards Take top and bottom card and make new pile the next top and bottom card go below the new pile Here's an example...
  32. Corpuscule

    Corporate Data Science after a PhD in Physics

    I would like to start a thread discussing the opportunities for Physics PhDs in the field of corporate Data Science. This emerging filed is briefly explained in the following article: http://www-01.ibm.com/software/data/infosphere/data-scientist/ I have heard on a number of occasions that...
  33. I

    Estimate Probability of Excel Data Analysis Results

    Not sure where to post this question, but here goes In excel I have calculated the average annual rain for the period 1990-2012 to be 50.2mm . How do you estimate the probability that this measured average (1990-2012) is consistent with the long term mean annual rain for the period 1948-2012...
  34. I

    Tabulate data from the mathlab program

    I need to tabulate the data for u(x,t) vs x. Someone help me please :( this is the program. L = 1.; T = 1.; maxk = 2500; dt = T/maxk; n=50; dx = L/n; cond = 1/4; b = 2.*cond*dt/(dx*dx); for i= 1:n+1 x(i) = (i-1)*dx; u(i,1) = sin(pi*x(i)); end for k=1:maxk+1 u(1,k) = 0...
  35. B

    Visualization of detector data / other ideas for viz application

    Greetings friendly physics folks, I could use some advice and/or general suggestions regarding a data visualization project I'm looking to get started on. If this looks like too much reading, please skip to the TL;DR below. The basic project components are: (1) A GUI of some kind...
  36. fluidistic

    Data analysis , I don't understand why this isn't a Gaussian nor a Ma

    Data "analysis", I don't understand why this isn't a Gaussian nor a Ma I have downloaded all the elo ratings of all active chess players in May of the FIDE and I have made an histogram. I have plotted the result on a graph rating vs number of people with this rating. I do not understand why...
  37. D

    Finding periodic best-fit equation for data set?

    Hello, I have a data set that follows an equation similar to sin(x)+x. Just from eyeballing the data, it seems like there should be a pretty simple trigonometric function A*sin(B*x)+C*x. I went to school for engineering so I have some basic/intermediate knowledge of mathematics but it's...
  38. R

    Can I use experimental data to solve equations with integrals?

    Hi, I don't know if this is the proper part of the forum to ask this, but I'm trying to figure out how I can obtain a certain value from an equation that contains an integral if I want to use experimental data. To keep it simple, the equation looks like this: B= (∫G(f)df)2 / (∫G(f)2df) where...
  39. E

    When is it ok to exclude data for a model to fit better?

    Hello people, I'm working on a research project involving the modelling of a black body's radiation spectrum, and near the limits of the spectrometer, the intensity goes to zero rather sharply. I cannot directly say it is error from the spectrometer, because I simply don't know. However, I...
  40. D

    Calculating Acceleration and Error for a Ball Rolling Down an Inclined Plane

    Homework Statement Calculate the acceleration of a ball rolling down an inclined plane and also note the error. I am going to solve it myself, so I will just give one sample. Distance covered by ball(error : +- 0.05 cm) .95m Time taken(error : +- 0.01 s) 1.19s Acceleration(with error)...
  41. M

    Mathematics courses useful in engineering, data analysis and modeling

    Hello, I am currently pursuing my degree in Mechanical Engineering, and was wondering what math courses were good to take after the basic math sequence has been completed (Calculus 1-3, Differential Eq & Linear Algebra.). I have an interest in mathematical modeling and data analysis, as...
  42. Albert1

    MHB Find AB: Solving $\triangle ABC$ with Given Data

    $\triangle ABC,$ point D and point E are on segment BC given: (1)AC=15, BD=9, DE=11, EC=5 (2)$\angle BAD=\angle CAE$ Please find AB=?
  43. maistral

    Step by step algorithm to calculate VLE data from Redlich-Kwong?

    I keep on reading that VLE data may be calculated from the Redlich-Kwong. In line with this, I have these questions: 1) How accurate is the VLE data generated with the Redlich-Kwong as compared to using the vapor pressures to calculate these VLE data? 2) Can you guys give me a link, or even...
  44. M

    Is this a waveform or random data?

    Hi there, I have recently come across some data that is supposed to be random, but I don't think it is. I graphed it out and it sure doesn't look random. I also ran a couple of statistical tests such as the runs test, and they all say "not random." Visually, the data looks like a piece of...
  45. D

    Non-Parametric Testing for Widget Defectivity: Sample Size Considerations

    Hi all. I'm trying to come up with a way to determine if the defectivity of a particular widget is 'different' to the usual defectivity of a widget. The difficulty comes from the fact that widgets are made in batches of 25. We'd like to investigate any widgets which have a higher (or lower)...
  46. N

    Kramers-Kronig relations on a finite data set

    Hi Say I have a finite data set (frequency, absorption) and I would like to find the corresponding dispersion. For this I could use the Kramers-Kronig (KK) relation on the absorption data. What I would do is to make a qubic spline and then perform the KK-transformation. However, the absorption...
  47. O

    Access Solar Radiation Data: UV-A, UV-B & UV-C

    Does anyone have access to the current data about solar radiation reaching Earth's surface ? The most importaint is the UV range divided into UV-A, UV-B and UV-C. If not, then data from the past few years would also be fine. I need it for research but I cannot find anywhere such information.
  48. H

    Understanding accelerometer data

    I'm having trouble understanding what accelerometers really measure. In observing a simple gravity pendulum, the accelerometer recorded this data (jpeg image attached) which is acceleration in the vertical direction (supposedly). Now I've been told all sorts of things, like that the...
  49. dexterdev

    How do we represent multidimensional data vectors on a 2D plot.

    Hi all, I would like to know if there exists any method to represent multidimensional vectors on a 2D plot so using extracting any unique features of those vectors. Can eigen values be used for such purposes like dimensional reduction. If so how ? I would like to know more about these...
  50. M

    MATLAB Matlab - area values into raster data

    I'm trying to transform area values into raster data. I have areas, defined as circles (location of center + length of radius). Each area has a designated value between 0 and 2. I used Matlab's command area to plot the areas and also to designate the value that goes with each area. Now I want...
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