1. 10-14-2010
Views:
20,404
Page 1 of 83 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 51 ... Last
Threads 1 to 60 of 4929

# Forum: Probability

Probability course and homework discussion. Probability distributions. Probability theory, stochastic processes

1. ### Sticky: We only provide homework help to those who show effort

Welcome to Talk Stats Forum. In order to keep homework help effective and efficient, we request all members to abide by these guidelines: 1)...

• Replies: 0
• Views: 12,362
09-30-2005, 09:44 AM
1. ### probability with mean and standard deviation

The local hardware store sells screws in 1lb bags. Because the screws aren't identical, the number of screws per bag, although distributed...

• Replies: 4
• Views: 57,070
03-06-2012, 04:20 PM
2. ### φ Distribution Table

Hi, I'm currently looking for the φ distribution table, to calcuate marginal effects in a probit model. Unfortunatly there isn't one in my...

• Replies: 0
• Views: 55,662
04-15-2011, 05:59 AM
3. ### Significance Test: Ho & Ha

Me again :) This is a long assingment I'm working on, and I have another question that I'm doubting my answer on.... This is the question: Q: ...

• Replies: 1
• Views: 51,497
11-13-2005, 08:40 AM
4. ### calculation of distance using Kullback–Leibler divergence

Hi, Basically I'm from biology back ground. So it may be a basic question for you. I have two plots for example plot1: X - axis values: ...

• Replies: 2
• Views: 50,121
03-03-2011, 08:39 AM
5. ### π-system and monotone class

Assume P is a π-system (that is, P is closed under finite intersections) and M is monotone class (that is M is a non-empty collection of subsets of Ω...

• Replies: 3
• Views: 49,328
BGM
12-17-2011, 09:54 AM
6. ### Express E[X-μ]^4 in terms of....

X is a random variable with moments E, E, E. Suppose var(X)= σ^2, skewness is given as S=/(σ^3). Express the right side of the following as in...

• Replies: 0
• Views: 44,824
10-16-2011, 10:52 PM
7. ### Μarginal Distributions of f(x,y)

f(x,y) = e^(-x), 0<=x<inf, 0<=y<=1 To find the marginal PDFs here is what I did so far: Marginal Distribution of x: f(x) = integral...

• Replies: 2
• Views: 40,071
10-16-2011, 12:42 PM
8. ### Calculating z value/mean and standard deviation

Hi...have completed my assignment (and have come a long way with some helpful tips on this forum) but am stuck on one problem: In grading apples...

• Replies: 11
• Views: 34,072
01-07-2006, 09:22 PM
9. ### Var(X+Y+Z)

What is the formula for the variance of 3 dependent variables? For 2 dependent variables, the formula is Var(X)+Var(Y)+2*Cov(X,Y) What is...

• Replies: 6
• Views: 33,842
02-09-2015, 01:15 AM
10. ### need assistance

I am taking a course in safety and now have one class left, but ran into a big problem. This class has statistics and I don't have a clue. The text...

• Replies: 5
• Views: 33,746
03-05-2006, 05:23 PM
11. ### Finding Mean and Variance for X^2 Given Mean and Variance for X

I am working on a question that has me stumped. X1, X2, ... Xn are normally distributed and independent. Each has a mean of 0 and variance sigma^2....

• Replies: 4
• Views: 30,380
11-08-2010, 05:47 PM
12. ### Probability Problem

Pls help...........:wave: My problem exercise goes like this - An employee of the records office at a certain school currently has 10 forms on...

• Replies: 74
• Views: 27,694
leo
06-04-2008, 07:00 PM
13. ### Binomial Probabilities

These kinds of questions can be answered using the binomial probability distribution: 1. If I flip a coin 20 times, what is the probability of...

• Replies: 0
• Views: 26,998
11-01-2005, 01:50 PM
14. ### Help! I’m baffled with a probability problem…..

Hi, Newby here. I am hoping someone on here can assist with a probability question that’s troubling me. I have three ‘events’, in each event...

• Replies: 4
• Views: 23,243
01-09-2012, 10:39 AM
15. ### E[MSE] simple linear regression

Hi All- I am trying to figure out how to prove that MSE = SSE/n-2 is an unbiased estimator of sigma^2 in simple linear regression. I have that...

• Replies: 14
• Views: 22,917
02-02-2013, 02:44 AM
16. ### Help about Isserlis’ theorem

The Isserlis theorem states that if is a zero mean multivariate normal random vector, then : E = EE + EE + EE Now, in the case x,y,z,t are...

• Replies: 0
• Views: 21,889
01-30-2012, 11:38 AM
17. ### The Probability of a Flush

Hiya :) Im back for some more assistance.... Q: THE PROBABILITY OF A FLUSH A poker player holds a flush when all 5 cards in the hand belong to...

• Replies: 1
• Views: 20,961
11-14-2005, 08:45 AM
18. ### I still need help please

Ok, so I am still working on this freaking problem. Can someone help me please. It states that the scenario is normally distributed with a mean price...

• Replies: 12
• Views: 20,662
12-14-2009, 08:10 PM
19. ### Expected Value of Exponential Distribution

I've almost completed this problem, but I'm stuck on the last part. The first two parts that I've already shown are also given: a) For a whole...

• Replies: 1
• Views: 19,792
07-03-2007, 01:24 PM
20. ### What is the meaning of kurtosis?

I found in Wikipedia that kurtosis is measurement of peakiness of the famous bell curve. If kurtosis is more than 3, it is kind of peaky, if kurtosis...

• Replies: 10
• Views: 19,456
11-09-2011, 11:39 AM
21. ### Z-scores for probability in tails

I haven't done any stats in years and now I am in a course for my grad program and I am so lost. My teacher is very confusing and I am trying my best...

• Replies: 3
• Views: 19,377
10-16-2008, 06:45 AM
22. ### Standard Deviation from Percentiles and Mean

Hello to all and thank you in advance for the help with this. I am working with a lognormal distribution and am given Percentiles - P10, P50, P90,...

• Replies: 7
• Views: 19,139
12-23-2010, 01:14 PM
23. ### MLE of a Gamma Distribution

Hello everyone, I'm having quite some trouble with a question about the maximum likelihood estimator of a gamma distribution. The question is as...

• Replies: 2
• Views: 18,733
11-26-2008, 12:24 PM
24. ### M.g.f for Poisson distribution

Hello, I am having trouble understanding the maths between E(e^{tx}) where I get a summation from 0 to \infty and the m.g.f for Poisson...

• Replies: 2
• Views: 17,647
01-07-2011, 12:55 PM
25. ### P-value from test statistic

I'm given a test-statistic of 2.4 in one of those H0 type problem with a 0.05 significance level. In the z-table, if you look up 2.4, it says 0.0082....

• Replies: 8
• Views: 17,505
01-01-2015, 09:33 PM
26. ### α = 0.05 vs p-value?

So I've got a couple questions on my stats homework as follows: E. Canis infection is a tick-bone disease of dogs that is sometimes contracted by...

• Replies: 4
• Views: 17,497
09-30-2012, 04:51 AM
27. ### mann whitney test or Kolmogorov smirnov test?

I'm working with non parametric methods to compare two samples and detect diferences between them. I used the mann-whitney test and obtained, for all...

• Replies: 23
• Views: 17,334
05-09-2010, 02:28 PM
28. ### Help with finding indicated probability

I have worked on this problem now for the whole entire day, and still don't understand what I am doing wrong. Can someone help me? The problem...

• Replies: 4
• Views: 16,742
07-13-2008, 06:04 PM
29. ### Geometric Distribution

A geometric Distribution is a discrete probability distribution of a random variable x that satisifies: 1. A trial is repeated unitl a success...

• Replies: 0
• Views: 16,656
09-14-2006, 05:48 PM
30. ### Can't understand some probability symbols.

For two events, A and B, P(A) =1/2, P(B) =1/3, and P(A �� B) =1/4. Find P(B | A). The symbol where is shows a box here is an upsidedown U. Does...

• Replies: 2
• Views: 16,531
06-17-2007, 01:00 AM
31. ### probability of one random variable being greater than another

I took statistics many moons ago, and remember performing these calculations, but for the life of me I can't remember what this process is called, or...

• Replies: 3
• Views: 15,476
BGM
04-22-2012, 12:38 PM
32. ### Doesn't "At least" mean greater than

Thank you for taking the time to read my question :) I was given a question that reads: We would like to test whether the percentage of students...

• Replies: 7
• Views: 15,398
09-27-2010, 10:35 AM
33. ### Standard Normal Variable Z ... I do not understand

:confused: Hi, This is not a homework question as I have the answer, just trying to figure out the method; I have a "Normal Distribution...

• Replies: 2
• Views: 15,019
04-23-2006, 02:33 PM
34. ### Sum of Poisson Distribution

Hi everyone. Let X and Y be independent, with X~Poi(lambda) and Y~Poi(mu). Put Z = X + Y as their sum. Find the distribution X | Z = z.

• Replies: 8
• Views: 14,372
02-13-2012, 06:50 PM
35. ### Permutations with Duplicates

I have been trying to find information about calculating permutations that include multiple duplicate items, but have only found programming source...

• Replies: 10
• Views: 13,591
10-30-2006, 02:34 PM
36. ### Maximum of a set of independent normal random variables

Consider a set of random variables X_1, X_2, X_3, \ldots, X_n with unit varience but different means: \mu_1, \mu_2, \mu_3, \ldots, \mu_n . What...

• Replies: 20
• Views: 13,154
07-12-2010, 03:45 PM
37. ### Conditional Probability - Exam

Someone can help me please, I need to understand them for my exam on Monday in next week. Today is Saturday.....Thanks a lot..... USING AND...

• Replies: 1
• Views: 13,121
07-29-2007, 07:05 PM
38. ### Combine Normal Distributions

How do you combine multiple normal distributions with different standard deviations and means, to produce one representative normal distribution? ...

• Replies: 12
• Views: 12,462
01-25-2013, 11:51 PM
39. ### Find E(X) and VAR (X)

Question is: There is one error in one of five blocks of program. To find the error, we test three randomly selected blocks. Let X be the number of...

• Replies: 8
• Views: 12,214
01-15-2012, 02:26 PM
40. ### Probability on a Multiple Choice exam

Hello, I am not very good at this type of stuff. I thought up something and I was wondering if someone can look over it and tell me if my...

• Replies: 18
• Views: 12,138
12-25-2011, 06:07 AM
41. ### Joint distribution, find P(X^2 + Y^2 <=1)

I am trying to teach myself (without a tutor) some degree level Statistics. I think I've answered parts a-c of this question, but would like...

• Replies: 6
• Views: 11,833
01-17-2009, 01:42 PM
42. ### Uniform Probability Distribution

The driving distance for the top 100 golfers on the PGA tour is between 284.7and 310.6 yards (Golfweek, March 29, 2003). Assume that the driving...

• Replies: 5
• Views: 11,746
BGM
04-11-2011, 01:53 PM
43. ### Creating a joint probability table

I need help figuring out how to create this joint probability table 43 million people in the United States go without health insurance. Sample...

• Replies: 3
• Views: 11,625
09-03-2009, 09:58 PM
44. ### Equation for the Standard Normal Curve

Does anybody know what the equation is for the standard normal curve? In my statistics class, we use a chart to find areas under the curve given...

• Replies: 6
• Views: 11,523
04-16-2010, 04:52 PM
45. ### Product Normal Distribution

Hi, Summing normal distributions is nice and easy, providing another normal distribution. But multiplying gives the Product Normal Distribution....

• Replies: 6
• Views: 11,495
01-20-2012, 11:54 AM
46. ### conditional binomial is a poisson distribution

Hi, I'm fighting with this problem for a while. There is something important I'm missing So the problem goes like this X~Poisson(lambda) and Y|X=k...

• Replies: 7
• Views: 11,281
BGM
06-11-2013, 08:59 AM
47. ### Exponential (θ ) distribution question

Xsub1 and Xsub2 are independent Exponential ( θ ), θ >0, random variables. Let S= Xsub1 +Xsub2 Write the PDF of S stating any standard...

• Replies: 1
• Views: 11,266
BGM
11-08-2012, 10:41 AM
48. ### Discrete Probability Distributions - Shoot me now!

I spent three hours at a basketball tournament trying to figure these out. Please help. Using the Poisson Probability Distribution I have the...

• Replies: 2
• Views: 11,158
02-13-2006, 08:58 AM
49. ### Normal Distribution times constant

I can't seem to find anything about this on the web. If I have a random variable distributed Normally: x ~ Normal(mean,variance) is the...

• Replies: 4
• Views: 10,707
02-18-2015, 08:45 PM
50. ### Calculating probability of multiple events

This is my first post so I hope I can get my question across reasonably intelligently. I have calculated the probability of an event occurring for...

• Replies: 3
• Views: 10,298
11-26-2008, 04:24 AM
51. ### variance of binomial distribution

The variance of a binomial distribution for which n = 100 and p = 0.20 is this is a practice problem for a test im taking next week. But i don't...

• Replies: 1
• Views: 9,854
02-23-2009, 08:46 PM
52. ### show P(N>n)=P(X_(n:n)−X_(1:n)<α)

suppose X1,X2,… is sequence of independent random variables of U(0,1) if N=min{n>0:X_(n:n)−X_(1:n)>α,0<α<1} that X_(1:n) is smallest order statistic...

• Replies: 0
• Views: 9,762
08-01-2012, 08:58 AM
53. ### probability of failure in a multi-component system

I want to calculate the failure rate of a system that has multiple independent points of failure. If any one of these intermediate points fail then...

• Replies: 2
• Views: 9,741
01-19-2010, 09:09 AM
54. ### probability of consumption

could someone let me know what i'm doing wrong? A study of the amount of time it takes a mechanic to rebuild the transmission for a 1992 Chevrolet...

• Replies: 4
• Views: 9,645
06-13-2007, 11:06 AM
55. ### Dependent Event Vs Independent Event Vs Mutually Exclusive Events

While reading probability book I come across with above terms. Following questions raised in my mind. 1)Are Dependent events always Mutually...

• Replies: 3
• Views: 9,472
01-15-2013, 09:04 AM
56. ### Events A and B with complements

Hi all, I will show the quest first and my work after. Given: P(A) = 0.3, P(B) = 0.8, P(AUB) = 0.9 A) Find P(A|B), P(A'nB), P(B'UA') B)...

• Replies: 1
• Views: 9,400
BGM
10-24-2010, 01:39 PM
57. ### Figure out if there is any statistical significance

Hi - I have some data on the internal temperature of cooked meat. The meat patty is a failure if the temperature obtained is below a certain...

• Replies: 8
• Views: 9,173
06-10-2010, 01:27 PM

Page 1 of 83 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 51 ... Last

Use this control to limit the display of threads to those newer than the specified time frame.

Allows you to choose the data by which the thread list will be sorted.

Note: when sorting by date, 'descending order' will show the newest results first.