Stats Definition and 227 Threads

Hey, I have never taken any stats course but I desperately need the answers to my questions checked out. We have a dataset with 5 independent and dozens of observational dependent variables, including location. The independent and dependent variables are sampled asynchronously! (the...

Homework Statement I am analyzing fuel economy of vehicles in Europe. Since there are gasoline (lower MPG) and diesel (higher MPG) I assumed the distribution to be bimodal. I am trying to deconstruct the data into a gasoline MPG and a diesel MPG. I have attached an image to explain my...

Hi, all. This is my first post. Although my question isn't directly physics related, I hope I will be able to get some feedback, as I haven't had much luck finding career advice forums for math & stats. I recently obtained a BSc with a major in Mathematics. This is not an honours or...

Hey everyone, Next year (sophomore year in high school) I will be taking pre-calc as of now. I was just dropping into ask if anyone thinks that it's a good idea to take AP-Stats along with pre-calc. I can't imagine myself having all that much trouble with it, as I do love math. Thanks for...

A university department has 2 secretaries (labelled A and B) who do all the word processing required by the department. The number of misprints on a randomly sampled page typed by secretary i (i=A,B) has a Poisson distribution with Mean Ui independent of the number of misprints on any other...

A university department has 2 secretaries (labelled A and B) who do all the word processing required by the department. The number of misprints on a randomly sampled page typed by secretary i (i=A,B) has a Poisson distribution with Mean Ui independent of the number of misprints on any other...

Homework Statement Determine the number of microstates where two particles have have energy 2eV, three have 3eV, three have energy 4eV, and two have 5eV. 10 indistinguishable Particles 1 particle allowed per state. ε1 = 1eV ε2 = 2eV ε3 = 3eV ε4 = 4eV ε5 = 5eV ε6 = 6eV g1...

Homework Statement An image of the assigned problem is here: http://imgur.com/aYkaM Homework Equations The formula for being exponential, gamma, and probably Bayes's Law. They'd take a while to type out, and presumably anyone who can help me with this already knows the formulas or...

Homework Statement I have taken a random sample such that X~N(8,2). I want to use the samples that I have generated to estimate E(xbar), E(s2), E(α21) and E(α22) for the population. Homework Equations The Attempt at a Solution I am not entirely sure how to do these. I know that for a...

Homework Statement Homework Equations The Attempt at a Solution I've tried putting this into a poisson distribution, binomial, negative binomial. I've tried to get the interval from 0-1 and subtracting that from 1 to find out what the probability is that the Random variable is X...

We are to prove sum(n)(I=1)(k(I))*(x(I)) = 1 Where (k(I))= (x(I)-x(bar))/(sum(n)(j=1)(x(j)-x(bar))^2 Attempt at solution: I rearranged it to equal: (1/(sum(n)(j=1)(x(j)-x(bar))^2))*(sum(n)(I=1)(x(I)-x(bar))*x(I)) I don't really know how to proceed. Sorry for the formatting...

Homework Statement According to genetic linkage theory, observed frequencies of four phenotypes resulting from crossing tomato plants are in the ratio 9/16 + a : 3/16 - a : 3/16 - a : 1/16 + a. In 1931, J.W. MacArthur reported the following frequencies: Observed...

Homework Statement There are balls numbered 1 through n in a box. Suppose that a boy successively draws a ball from the box, each time replacing the one drawn before drawing another. This continues until the boy draws a ball that he has previously drawn before. Let X denote the number of...

Homework Statement A die is rolled until the first time that a six turns up. We shall see that the probability that this occurs on the nth roll is (5/6)n−1 · (1/6). Using this fact, describe the appropriate infinite sample space and distribution function for the experiment of rolling a die...

...or more likely, I'm just being retarded. So here's the offending statement: Let X be our random variable with a countable range of {x_1, x_2, ... , x_n, ...}. Let f(x) be a discrete density function and F(x) the corresponding cumulative distribution function. Then, f(x_j) = F(x_j) -...

I missed the lesson on this and i can't figure out how to do this question with the data given. Homework Statement A class of 20 students takes a test. The score, x , for each student was recorded by the teacher. The results of summarised by: ∑(x-10) = 208 and ∑(x-10)² = 2716 i) calculate...

Hey guys, Basically I have a component that I want to test multiple times. The outcome of each test is simply a Pass/Fail. What I want to know is how many tests do I have to do to be (say) 95% sure that I have the right result? My stats knowledge is a bit hazy but I know that for these...

Hello everyone, My boss has asked me to find if there is any correlation between various sample parameters in a water quality study. We took around 150 samples, and for each one measured around 50 parameters e.g. iron content, free residual chlorine, level of coliforms, pH, etc etc. I...

Homework Statement 265 students hire a tutor to help them improve their scores on the SAT test. The results are summarized in Math and Verbal score changes. Math: Mean change in score = 19, Standard Deviation of score changes = 65 Verbal: Mean change in score = 7, Standard Deviation of...

Homework Statement I am given a table of x and Probability of x an I have calculated the standard deviation and the variance. Homework Equations The Attempt at a Solution from here how do I calculate the probability that a value is within one standard deviation

Homework Statement 4 temperature measuring instruments were compared. readings were taken at 10 points (as temp was increased) 2. The attempt at a solution the wording of the question is what's confusing me. Is each instrument going to have one value for deviation? Or is it asking for a...

Homework Statement so in general, i am having difficulty in figuring out the range of a transformed variable. sometimes it's easy, i just plug in values and get the other values out, but sometimes I'm not seeing it. for example: f(x)=4x3, for 0<x<1 and let U = (X-.5)2. Finding the pdf of U...

I'm a computer engineering major and I would like to work designing hardware and systems. I believe I'm a great inventor and think in a very abstract fashion. My grades on non math classes stink, but my math and physics grades are well above the "A" curve. Scoring from 85-100 on exams. points of...

For the key stuff, just glance at the bold statements and my program choices. So; I tend to think that my stats are pretty iffy, but I'd like to see if I can get any input. I'm applying to a variety of programs (though I'm only putting up the math and stats choices here) because I've got a...

I will try to be brief, so please bear with me! I have a Matlab program which simulates a particle's movement over time in a certain ocean. The details of this implementation aren't really important, but basically I create about ~300 particles near each other and place them at a certain...

(I asked this question in the Stack Exchange http://stats.stackexchange.com/questions/13014/how-to-combine-the-results-of-several-binary-tests" , but didn't get anything that was helpful to me.) I'm a programmer (former EE) working on a medical application. My last stats course was in...

I am home for the summer and trying to learn a decent amount of software. I already know about AutoCAD, Inventor, etc. but I can't find anything from them that lasts more than a month and has features removed maybe someone could point me out to a special offer? Also, what are the more popular...

Hi, I'm deciding whether or not to take AP Stats. I will be taking Honors Physics and AP Calculus AB and AP Latin. I've read that only Calculus-based stats is useful for Engineering. I don't want to take all three courses because I don't want to kill myself. Is AP Stats absolutely...

The probability density function of the time customers arrive at a terminal (in minutes after 8:00 A.M) is f(x)= (e^(-x/10))/10 for 0 < x c) Determine the probability that: two or more customers arrive before 8:40 A.M among five that arrive at the terminal. Assume arrivals are...

http://www.npr.org/blogs/money/2011/05/23/136461536/whats-a-millionaire?sc=fb&cc=fp Are these numbers correct? One in every 400 US households make more than $1 million a year? One out of every 15 U.S. households has at least $1 million in assets?

Water shortages require water rationing policies. From past records, we know that the probability that water needs to be rationed in a southland water district in any given year is 0.15. Assume that water rationing in consecutive years are independent events. Let X be the number of years with...

Homework Statement in a genetics situation, we have two variables, x1 and x2, such that both x1 and x2 >0, and x1+x2<1. we have: p1 = x12 p2 = x22 p3 = (1-x1-x2)2 p4 = 2x1x2 p5 = 2x1(1-x1-x2) p6 = 2x2(1-x1-x2) find the mles for x1 and x2. Homework Equations the answer (from the...

In any significance test, if the result is greater than the cutoff it is not significant, if the result is less than the cutoff it is significant. What if it is exactly equal to the cutoff (.05) is it significant or not?

Homework Statement So here's the problem. There is an elevator w/ 5 people equally likely to get off at any of the 7 floor. What is the probability that no two passengers will get off the same floor. Homework Equations The probability of event should be P(E)= number of event...

Hello, I am faced with a perplexing challenge in analyzing my results for an ecology experiment. All help is immensely appreciated. The situation: I have 6-month longitudinal mass data for 8 hummingbirds. From eye-balling the data, time definitely has an effect: masses tend to decrease...

Homework Statement [PLAIN]http://img822.imageshack.us/img822/4421/statsii.jpg The Attempt at a Solution Done parts (a) and (b). How do I do parts (c) and (d)? Is the simple linear regression model just Y_i=\beta_0+\beta_1 X_i + \varepsilon_i where \varepsilon_i \stackrel...

(nod'n'smile to all) Not a terribly important question, but i feel piqued curiosity without question is against forum rules.. i am a <week old member, just noticed my post count still shows zero. I don't have an accountancy OCD but i don't want to be the "new kid" forever..:rolleyes: ...

Pick one card from a deck, then throw it away. Now pick another card from the remaining 51 cards. What is the probability that card is an Ace? Pick 5 cards from a deck and throw them away without looking at them. Now pick another card from the remaining 47 cards. What is the probability that...

My friend and I have begun work on a folding at home statistics site. I'm going to break F@H down for you all real quick. Every 3 hours a Team submits more points and "Units" to their total points and Unit count. (The unit is where the points come from). So every 3 hours Point and Unit...

I'm not sure what to major in but stats is appealing to me more all of a sudden. Probably because I'm scared i can't get a job with a math degree. Which is harder though? Which one has more rigor? Which one will earn me more money?

Homework Statement [PLAIN]http://img222.imageshack.us/img222/2781/statsqk.jpg Homework Equations f_{X} (x) = \int^{\infty}_{-\infty} f_{X,Y} (x,y)\;dy f_{Y} (y) = \int^{\infty}_{-\infty} f_{X,Y} (x,y)\;dx f_{X|Y} (x|y) = \frac{f_{X,Y} (x,y)}{f_Y (y)} f_{Y|X} (y|x) =...

I was doing tech support at a healthcare conference over the weekend in which one of the speakers talked about stats 101 and interpreting research. In discussing it further with my wife this morning, I realized we've missed a piece of the puzzle. My wife made an spurious example of cars...

Hi Physics Forum, lurked around a bit and need some advice. I've never particularly liked any branch of my academics, however I excelled in my English classes and I thought the most natural thing to do was declare it my major. I absolutely hate academic reading though, as I see it mostly as a...

Homework Statement Let X have mean u and variance s^2. Find the mean and the variance of Y=[(X-u)/s]Homework Equations The Mean is linearThe Attempt at a Solution I thought to just plug in the mean of X anywhere i saw it in Y so mean of Y would be 0 and then for the variance I was kind of...

I've heard mixed opinions regarding the importance of the PGRE. I heard from some that the PGRE has no relevance at all, as some profs on the admissions committee don't even LOOK at it. However, I've of course heard from others that its very important I've heard plenty of people with great...

Hi everyone, I have trouble depicting the difference between these two problems. The first problem uses the multiplication rule to solve while the second problem uses the counting rules (combination) to solve. To me, it seems like both problems could be solved using the multiplication rule so I...

I am having a difficult time grasping the multiplication rules - The rules are easy to remember but actually applying it to a problem is so confusing and frustrating as I don't know whether to use Rule #1 (independent events) or Rule #2 (Dependent events). Here's a problem from my book that I...

Hey guys, this is for an elementary statistics course. When given a problem, I am having trouble determining which is the data set (X) and which is the weight (W). For example: Using the weighted mean, find the average number of grams of fat per ounce of meat or fish that a person would...

I really understand most of the question, just having trouble with one part, so I am going to try to sum it up. if you need more info to clarify please let me know... background... nielson media research provides two measures of television viewing audience (in this case for the world...

I'm majoring in Physics and minoring in Math at a highly ranked liberal arts school (top 25). I have a 3.9 overall GPA and I'm not sure what my math and Physics GPA is but its higher than 3.9. I have all A's and one A- in math and Physics. I got an 800 on the quantitative section of the GRE...