Stats Definition and 227 Threads

Ok, I'm sure I can find a smarter way to pose this question, and I will try to define the question more carefully in coming days. That having been said, consider this: Let's say we have a random variable X (or whatever). I can calculate the moments of this variable with no problem. In fact let's...

I’m analysing the gravitational relationships between different mass astronomical bodies and am getting sick of having to individually google and document these. Are there data sets out there that list pairs/sets of objects which includes their mass and distance from each other? Including...

Per Worldometer 2022/18/03 18:51 MDT data: Reported Covid US deaths 997041, World deaths 6093047 Population of the US 334256039, World (est) 7934365211 USA as % of world population 4.2% USA as % of world Covid deaths 16.3% In a short while the Worldometer counter for USA deaths will hit 1...

Can you please suggest a good introductory statistical and quantum mechanics book which can be self studied. My math background : I've done multivariate calculus, vector calculus, linear algebra ,some complex analysis all at the usual undergraduate level. The books I've self studied thus far...

Hello, I am a senior physics student who is interested in applying to graduate school for physics. I am having a hard time figuring out where to apply, what my safe, match and reach schools are, and in general deciding where I can even get into if I apply so I don't waste hundreds of dollars on...

Question: In finance, the strong form of the efficient market hypothesis states that studying financial information about stocks is a waste of time since all public and private information that might affect the stock price is already reflected in the price of the stock. However, a study of 450...

Now I don't really know much about the subject, I'm primarily just peaking into my textbook to see how to solve this or that exercise. I believe I can figure out how to solve the third question. However I couldn't find how to solve the first two. I know how to find a 95% confidence interval for...

In "Introduction to Quantum Mechanics", Griffiths derives the following formulae for counting the number of configurations for N particles. Distinguishable particles... $$ N!\prod_{n=1}^\infty \frac {d^{N_n}_n} {N_n !} $$ Fermions... $$ \prod_{n=1}^\infty \frac {d_n!} {N_n!(d_n-N_n)!}$$...

Question: A home security device with 10 buttons is disarmed when three different buttons are pushed in the proper sequence. (No button can be pushed twice.) If the correct code is forgotten, what is the probability of disarming this device? My attempt: 10!/(10-3)! =(...

I don't know much about batch, but what I want is to execute a command such as ping google.com -n 200 and store all 200 ping latency results to a variable. The default results (avg max min %lost) isn't enough for me to tell if I can do what I need to do. I would like to calculate the average...

I'm not quite sure if my problem is considered a calculus problem or a statistics problem, but I believe it to be a statistics related problem. Below is a screenshot of what I'm dealing with. For a) I expressed f(t) in terms of parameters p and u, and I got: $$f(t)=\frac{-u \cdot a + u \cdot...

All, https://jimgrange.wordpress.com/2015/12/05/statistics-tables-where-do-the-numbers-come-from/ This is a great post -- but I'm a little foggy on the sentence that says "...mean and standard deviation for each condition is fixed at 0 and 1." Can someone explain this in a slightly different...

Hey everyone, So lately, my friends and I have been playing a card game (magic, because we're nerds :P) and we've been trying to rank our decks (as well as our probabilities to win a game, a match, etc). I've begun working on a spreadsheet with some initial data points (about 30 in total). The...

Hi, my main sticking point with the following is which bit of statistics/probability theory is needed to answer the question. We've only been taught basic Bayes theory, the standard pdfs and a little on hypothesis testing. I have spent way too much time just trying to figure out where to start...

I'm doing 1st year IT in uni and have maths questions which are beyond me, please help! Question 5 is causing me issues!

Hi there, not sure whether this is in the right section but: I've made two runs of a radioactive decay experiment where I've got a log(N) vs. time plots. From this I've got the decay constants and hence the half-life. I've averaged these two half-lives ( = 160 secs) and now I'm trying to work...

Homework Statement Consider non-decreasing series of numbers: 1, 8, 8, 13, 14, 14, x, y, 18, 20, 31, 34, 38 and 40. Median is 15 Calculate mode Homework Equations Median is middle term for odd number of terms and it's average of middle 2 terms for even number of terms. 3 Median = Mode + 2 Mean...

So I have a MS in Stats and a BS in Applied Math. For various reasons not related to raw ability, my GPA in Stats turned out to not be so good( 3.4) but my math GPA from undergrad is excellent ( 3.8). Should I even attempt continuing on in Stats or can I start over with a fresh plate in Applied...

I am aware that f-tests can be used to check the null hypothesis when comparing regression models if the models are nested. What I am confused about is if I can apply an f-test to compare the following, (and if so what is the best way) I have two regression laws Y = a1*X1 + a2*X2 + b Y =...

Hi All, Currently on a distance learning HNC and I am not quite sure whether the question just wants me to answer 'yes' or give mathematical evidence. Part A answered, Part B not sure... Any help would be great! 2. The process for the production of an electrical device is suitable for...

Homework Statement An assembly line is observed until items of both types—good (G) items and items not meeting specification (N)—are observed. Show the sample space. Homework Equations Let G be Good Let N be Not Good The Attempt at a Solution S = {GN, GGN, GG...N, GG..., NG, NNG, NN...G...

I am currently enrolled in a statistics course, and the following is stated in my course book with no attempt at an explanation: Suppose that f is the probability density function for the random variable (X,Y), and that F is the distribution function. Then, f_{X,Y}(x,y)=\frac{\partial^{2}...

Homework Statement From various studies, it is known that once an individual is infected with a virus, they become infectious at rate λ. The individual will recover at rate λ, independent of the time it took for them to become infectious. Let X be the total amount of time an individual has this...

Hey everyone, I'm a CS major, and haven't been using calculus 1 or 2 for over a year and a half now. I vaguely remember any of it other than basic concepts (what derivatives and integrals are, second derivative, inflection points, etc.). I am taking an Introduction to Probability and...

Homework Statement [/B] Driving to work, a commuter passes through a sequence of three traffic lights. At each light he either stops, denoted by s, or continues, denoted by c. Assume that the outcome c or s for each traffic light is independent of the outcome of other traffic lights. (a)...

Homework Statement [/B] There are six pairs of cups and saucers; two are red, two are white and two blue. 1. Ignoring the saucers, calculate the number of distinct arrangements of the cups. 2.Determine the number of distinct arrangements such that no cup is on a saucer of the same pattern for...

Hi, I am wanting some advice on about studying applied math or pure math. I have finished my 2nd year at uni and will be starting my 3rd year soon and have been thinking about changing my major from pure to applied (I also major in statistics as well). After I graduate I would love to do...

I'm two semesters away from graduating, after which i will get a masters degree in stats. My last semester is basically just one where i take courses I want while i wait for grad school to start, because i will have graduated after the semester after this current semester. Which COMPUTER SCIENCE...

Hi, I wasn't sure where to post this. I have a chemistry homework problem, which is not necessarily that hard, but it wants me to put values into my TI-84 Plus. I will not explain the problem too deeply, but it's about reaction time, volume, and concentration (mol/L). I am given a table of...

Hi, I have loaded the milkyway database of the design to the synopsys ic compiler how can i get details of all the cells present in the design or the netlist after place and route ? Thanks :)

Homework Statement Joan’s finishing time for the Bolder Boulder 10K race was 1.75 standard deviations faster than the women’s average for her age group. There were 405 women who ran in her age group. Assuming a normal distribution, how many women ran faster than Joan. Homework Equations The...

hello. I was originally planning to get a BS in statistics but then i chickened out because i feared that i might not be mathematically gifted/strong enough to get through the program, which would result in me not having the very basic in today's world : a bachelor's degree. So i switched to...

Homework Statement Please help! I'm new to Gaussian and I've been on this problem for hours, I can't crack it at all (no pun intended) can anyone provide a detailed walk through the answers? On average 5% of eggs contain a hereditary condition. Use Gaussian distribution to find the...

Getting ahead with my S1 & S2 for my further maths mods next year, really stuck on this particular question, as there is no such successive trials etc, please help me solve, so i can make some actual sense of what the hell is going on! Cheers, roughly that the portion of families with access...

Homework Statement Given that r≥(n-1)/(k^2) a) Show that the proportion of observations for which |di | ≥ k cannot exceed 1/(k^2) b) For what values of k is this meaningful.The Attempt at a Solution [/B] a) (r/n)≥(n-1)/(n*k^2) (r/n)≥(n-1)/(n*k^2) (r/n)≥(n)/(n*k^2) -1/(n*k^2)...

Homework Statement (1) Let the random variable X be the body temperature in ◦C for a randomly chosen person during waking hours. X is assumed to be a normally distributed with mean E(X) = 37.5 and standard deviation sd(X) = 0.3. Let Y be the body temperature in ◦F for a randomly chosen person...

Homework Statement (4) (a) Let X be a random variable defined by the probability mass function P(X = x). The possible values X can take (denoted x) and the probability of those values occurring P(X = x) can be seen below x 0 1000 2000 5000 P(X = x) 0.94 0.03 0.02 0.01 Find E(X). (b) An...

Homework Statement (4) (a) Let X be a random variable defined by the probability mass function P(X = x). The possible values X can take (denoted x) and the probability of those values occurring P(X = x) can be seen below x 0 1000 2000 5000 P(X = x) 0.94 0.03 0.02 0.01 Find E(X). (b) An...

Homework Statement [/B] A bowl contains a large number of M&Ms. A single M&M is chosen at random, its colour is observed, and then it is returned to the bowl. A second M&M is chosen at random and its colour is observed. Let A be the event that the first M&M is yellow and B be the event that the...

Homework Statement A multiple choice test consists of a series of questions, each with four possible answers. How many questions are needed in order to be 99% confident that a student who guesses blindly at each question scores no more than 35% on the test? Homework Equations So I know that...

Just like it says on the tin. Looking for recent statistics on global traffic by various (preferably application layer) protocols (i.e., DNS, HTTP, SMTP, etc.). Closest I can find are some regional and national breakdowns, but mostly from a lay reader's point of view.

Often in empirical studies you see statements that factor X explains some fraction of the variance in some other variable V, and thinking about what this means intuitively made me curious about the following question. Suppose you have a model where the values of some set of factors X1, X2, ...

I am a physics major deciding between taking either Statistics or Foundations of Higher Mathematics this semester. Neither are major requirments. Foundations of Higher Math covers logic, set theory, proofs, number systems, and some basic analysis. Elementary to Intermediate Statistics and Data...

Homework Statement An engineer is measuring a quantity q. It is assumed that there is a random error in each measurement, so the engineer will take n measurements and reports the average of the measurements as the estimated value of q. Specifically, if Yi is the value that is obtained in the...

Homework Statement The number of customers visiting a store during a day is a random variable with mean EX=100and variance Var(X)=225. Using Chebyshev's inequality, find an upper bound for having more than 120 or less than 80customers in a day. That is, find an upper bound on P(X≤80 or X≥120)...

I study a textbook in Discrete Math 7e Rosen , I am in ch.4 Number Theory Mainly for computer science improvement (cs) Is it ok study same time a Probability & Statistics textbook again for cs...? I have background in Calculus I II and Linear Algebra & web development.

Homework Statement Consider two random variables X and Y with joint PMF given by: PXY(k,L) = 1/(2k+l), for k,l = 1,2,3,... A) Show that X and Y are independent and find the marginal PMFs of X and Y B) Find P(X2 + Y2 ≤ 10) Homework Equations P(A)∩P(B)/P(B) = P(A|B) P(A|B) = P(A) if independent...

Homework Statement Suppose you take a pass-fail test repeatedly. Let Sk be the event that you are successful in your kth try, and Fk be the event that you fail the test in your kth try. On your first try, you have a 50% chance of passing the test. P(S1)=1−P(F1)=1/2. Assume that as you take the...

Homework Statement 50 students live in a dormitory. The parking lot has the capacity for 30 cars. If each student has a car with probability 12 (independently from other students), what is the probability that there won't be enough parking spaces for all the cars? Homework Equations P(A) =...

Homework Statement For reference, this is the image setting up the problem. "A wireless sensor grid consists of 21×11=231 sensor nodes that are located at points (i,j) in the plane such that i∈{0,1,⋯,20} and j∈{0,1,2,⋯,10} as shown in Figure 2.1. The sensor node located at point (0,0) needs...