Bias is a disproportionate weight in favor of or against an idea or thing, usually in a way that is closed-minded, prejudicial, or unfair. Biases can be innate or learned. People may develop biases for or against an individual, a group, or a belief. In science and engineering, a bias is a systematic error. Statistical bias results from an unfair sampling of a population, or from an estimation process that does not give accurate results on average.
Hello,
I understand that we have a population of values. We don't know the parameters of this population. The parameters are numbers, each one describing the population in a collective sense. Examples of parameters are the mean, the median, the mode, the variance, skewness, kurtosis, etc.
We...
I thought maybe we should have a thread about these software as there are probably interesting artifacts about them and they are just interesting in general
So here is an interesting fact I just found out while messing randomly with chat GPT.
I asked it a simple question - "5 best jokes about...
I was thinking that the probability of a set of events not happening is the same as the probability of that the die/coin is biased.
So, if I flip a coin 10 times and get heads every time, the probability the coin is biased is 1- (.5)^7.
Roll a die 5 times, get "4" all times, probability of...
Hello! I am using a mixture density network (MDN) to make some predictions. My model is very simple with one hidden layer only with 10 nodes (the details of the network shouldn't matter for my question but I can provide more if needed). Also my MDN has only one gaussian component which basically...
I came across an academic article by Mary Olson entitled "Disproportionate Impact of Radiation and Radiation Regulation" (https://www.tandfonline.com/doi/abs/10.1080/03080188.2019.1603864). Based on data in BEIR VII, she illustrates that women are more sensitive to ionizing radiation than men...
There is this slight bias, that I will explain in a moment. But it is quite easy to do a calculation to compensate for this bias and show that it makes next to no difference. Could I ask people to check that the explanation and calculation are correct please?The bias, and the calculation to...
Semi-random question: I generated dark and bias master frames (and from those, bad pixel maps) about a year ago. I'm sure my camera sensor has degraded over time.. b/c entropy... and so I'm wondering if it's worthwhile to create a new set. How often do you 'update' your dark and bias master...
In MOSCAP, why does the band stop bending as soon as the Si Fermi level touches either the conduction band (inversion) or the valance band (accumulation)?
It was not what I thought it would be, but I do observe such bias in papers/journals I read, and it is only part of the problem.
Researchers find citation bias in published papers and evidence that the problem is getting worse...
https://phys.org/news/2021-11-lack-massive-black-holes-telescope.html
I wonder how this affects the 'known', or rather, 'observed', mass in the galaxy and universe.
A very "meta" idea crossed my mind today, and I'd like some feedback. Apologies in advance in case the half-formedness of said idea results in a meandering post.
The specific connection I made was that the creation-versus-evolution "debate" could be characterized, at its most basic, as the...
I have a graph of mean signal (per pixel) vs exposure time (sec) for 8 different dark frames. I am being asked to find the bias in ADUs/pixel and the dark current in ADUs/sec/pixel and I am very confused on how I could get it. I know that the average of all of the mean signals is a rough guide...
Suppose there are two persons A and B such that both have a personal communication system which can transmit and receive bits. B has a biased coin whose bias is not known. A asks B to toss the coin 2000 times, send a 0 when a tail comes up and a 1 when a head comes up. It is known that whatever...
Hi,
In simple regression for machine learning , a model :
Y=mx +b ,
Is said AFAIK, to have bias equal to b. Is there a relation between the use of bias here and the use of bias in terms of estimators
for population parameters, i.e., the bias of an estimator P^ for a population parameter P is...
This post is slightly different from a previous post sent to mathematical forum : this is because I talk about here the MATLAB function "eig" with 2 arguments but this concerns actually the combination between 2 biased tracers in Cosmology context.
I am looking for a common basis of...
Hi. I'm an undergraduate student and I've been doing research in Civil Engineering for a couple years now. One thing which I've thought about repeatedly is a bias toward the desired result. Of course sometimes people might be biased for some ulterior motive or sloppy work, but the bias I'm...
There have been many studies done to find out if cell phones cause infertility. Most have found that there is a positive connection between phone use and infertility. However, most studies are done at fertility clinics and their study population is fertility patients. My question is, does the...
You are given the opportunity to play a game where a coin will be tossed 10,000 times consecutively.
You have a starting bankroll of $1,000,000.
The coin may be biased (you are not given any information as to what the probability or the degree of bias might be). A bet on either heads or tails is...
We are given that ##i_D = 8\cdot 10^{-12} (e^{v_D/20m} - 1)##
Hence ##i_D' = e^{50 v_D}/2500000000## and ##i_D'' = e^{50 v_D}/50000000##
Then I have that ##\delta i_D \approx\frac{ e^{50 v_D}}{2500000000} \cdot \delta v_D = \delta v_D / 5## Cancelling ##\delta v_D## from boh sides and solving...
Excuse me, I am not too well versed in statistics. I am in engineering.
Let's say I have an expected measurements(grand mean of values) and then I take another measurement of two different samples. Each sample is measured a few times to get it's own standard deviation and expected value.
I...
i have been researching how to build a boost converter. according to the articles i have read, when the switch is closed current flows through the
switch to the negative terminal. when the switch is opened, the back emf from the inductor and input voltage add, which forward biases the diode.
i...
From this article : https://arxiv.org/pdf/1611.09787.pdf , I try to deduce the equation that my teacher told me which links 2 quantities :
1) the global number density of galaxies
2) the local number density of galaxies
3) the contrast of Dark matter density
The relation that I would like to...
Hello!
I've done tons of research on a problem and can't seem to figure something out. I'm looking at operating a photovoltaic PIN photodiode. Since it's operating in photovoltaic mode, it will produce a current when light hits it, and this will produce a forward voltage.
I've researched...
Assume we have a closed diode circuit .We connect the n type region of the diode to the positive terminal of the battery.We connect the p type region of the diode to the negative terminal of the battery.The depletion layer is increased.Now we open the circuit.Why the diode returns to its zero...
Let X1, · · · , Xn be a simple random sample from some finite population of values {x1, · · · xN }.
Is the estimate \frac{1}{n} \sum_{i}^{n} f(Xi) always unbiased for \frac{1}{N} \sum_{i}^{N} f(xi) no matter what f is?My thinking: I don't think all f's are unbiased, because not all sample...
When a bias is applied to a wire, due to the resistance of a wire, the electrons colliding with the atoms make the wire warmer. However, we know that without any bias the electrons also move with very large velocity (of the order 10^5 m/s). How about the collision of these rapid electrons with...
This is assignment related, however it’s not really a problem solving question.
So we were to take darks from our school’s CCD. The manual for the CCD says there should be ~1000 ADUs/pixel for the bias, my graph (as well as many other people- they had similar numbers) says that the bias should...
If two batteries are connected such that positive terminal of one is in contact with negative terminal of other then we add the potentials so the potential will then be their sum.
Similarly if a battery is connected to a pn junction diode such that positive terminal is connected to negative...
Hello all,
I am having a very hard time understanding the operating principles of solar cells. I'm mostly confused about what external biasing conditions a solar cell operates under. I have tried googling this question and I get different answers (see the links below). For the TL;DR version...
I have frequently read and heard that mastering physics is the ultimate way to mold a problem-solving mind. Therefore, becoming a physics major is supposed to be the best way of doing so. I wonder to what degree that statement holds true.
Is it true? Is it biased? Am I misinterpreting...
Hello I am trying to check if the Method of Moments and Maximum Likelihood Estimators for parameter $\theta$ from a sample with population density $$f(x;\theta) = \frac 2 \theta x e^{\frac {-x^2}{\theta}} $$
for $$x \geq 0$, $\theta > 0$$ with $\theta$ being unknown.
Taking the first moment of...
I've been following, albeit loosely, the use of big data to refine astronomical data. It has been frequently noted that astronomy is an excellent test ground for big data approaches. I'm led to wonder what kind of results have been achieved to date and how effective are these methods for...
My general question is:
What is the angular power spectrum C_{l,N,ω} of N weighted (weight ω_i for event i) events from a full sky map with distribution C_l?
I'm interested in:
Mean of C_{l,N,ω}: <C_{l,N,ω}>
Variance of C_{l,N,ω}: Var(C_{l,N,ω})
The question is important, since we observe in...
I'm creating a project where the motors have to be triggered by a photodiode. A light provides a steady stream of current to the photodiode and when that incident light is scattered, the motors move. But in reverse bias a photodiode needs to have a dark environment to provide 'infinite...
Firstly, and most importantly: I am not interested in getting into a debate about climate change in this thread. If you try to engage in debate with me in this thread, I will immediately abuse my administrative powers and physically delete your post! (Devil)
Secondly, I want to make it clear...
The depletion layer is formed by the movement of electrons from the n to p side and holes from p to n side of the diode. The layer consists of positively charged donor ions close to the n side and negatively charged acceptor ions close to the p side. When in equilibrium,the barrier potential...
I've heard tell of a science journal like Science or Nature that a) only publishes studies with null results, and/or b) only publishes heavily replicated studies. Is this true? and if so, what's it called?
Why don't we consider the current produced by voltage source in plotting reverse bias characteristics?if this current is considered then the saturation current will depend on the the external voltage.
What happens if I for example, connect an Earth referenced bias voltage to the gate/grid/input of a mosfet/tube/opamp that uses a floating power supply?
Does the bias simply not work or does the circuit somehow become Earth referenced?
I don't know if it's the best place to ask this, but oh well... how to use the term "bias"?
What is the meaning of bias? I always thought that biasing a measurement meant something like "enforcing" some of its results, as for example predetermining what you want to get and so biasing it...
Hi!
When dealing with a pn homojunction, it is easy to see the features it has at equilibrium, and also the features it has with forward/reverse bias. Plots show the constant Fermi level at equilibrium and the different Fermi levels for a forward bias; moreover, examples show how much the bands...
With social science courses, there's lots of opinions and perspectives. I think it's inevitable that the professor will lean one way or another, and I don't think having an opinion is bad insofar as you're overall fair about the class.
One professor I knew taught in Introduction to Global...
Hi guys,
I was given this Mesa Boogie Nomad 45 chassis. I repaired it yesterday and have it working more or less well.
Mesa does not install adjustable bias in any of their amps. I want to install a trimmer pot to control the bias.
Where in the circuit should I place the trimmer resistor and...
Will this circuit work for maintaining a dc bias on the capacitors? I am under the impression that there is +4 v at point A; even if an emf charges and discharges the capacitors. I worry that current will flow into the battery.
How much current can be forced through a photovoltaic (solar) cell before its performance starts to deteriorate? In certain accelerated lifetime testing 1.25xIsc is forced through a solar module while it sits inside a chamber (no incident light). Is there a theoretical limit to the amount of...
Can someone explain why after a certain voltage, current flows. We were taught that in pn junction when a reverse voltage is applied the depletion region grows wider. Using this no matter what the voltage current should not increase. So why does a current flow when a reverse current is applied.
Hello,
I'm attempting to use a photodiode as a light intensity sensor. However, I have a question regarding the operation of a photodiode in a reverse biased position. The current going through the photodiode is dependent on the light received, and is not affected much by the reverse biased...
Hi PF,
I can't decide which path I should go down in terms of my focus. I really love digital hardware from FPGAs to doing IC layouts, I also enjoy the trade-offs involved in making a computer architecture. I also like analog circuits with things like mosfets and opamps. I think it would be...
WARNING. I'm not a physicist! If there was a universe that only had 10000 photons and we observed all of them then ran the double slit experiment would we get a normal pattern or an interference pattern? If we observe a particle is that it forever in the universe that we happen to be running...