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Forum: Statistics

Statistics course and homework discussion. Elementary statistics.

  1. Sticky Thread Sticky: Forum Guidelines: Smart posting behavior pays off

    Welcome to talkstats.com, the place for statistics help. This is a guideline for people who want to ask a question on this forum and value a...

    Started by TheEcologist‎, 11-27-2010 12:13 PM
    • Replies: 1
    • Views: 196,542
    07-16-2014, 11:01 AM Go to last post
  2. Arrow Sticky Thread 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)...

    Started by quark‎, 09-30-2005 09:44 AM
    • Replies: 0
    • Views: 66,610
    09-30-2005, 09:44 AM Go to last post
  1. Equations from properties of estimators

    From my textbook, on the chapter on properties of estimator I get the following: E(1/n*∑Yi^2-2Yi*Y︠+Y︠^2)=E(1/n*(∑Yi^2-n*Y︠^2) I get instead...

    Started by Francesco‎, 10-25-2012 05:37 AM
    • Replies: 1
    • Views: 1,019
    10-25-2012, 12:33 PM Go to last post
  2. How to report correlation in graph?

    Hi, I am trying to determine whether there is correlation between the body size (measured as size of wing) with energy reserves (measured as day...

    Started by hianghao‎, 10-24-2012 08:04 PM
    • Replies: 3
    • Views: 3,772
    10-25-2012, 09:08 AM Go to last post
  3. Expectations Question ~ One within another, assigning grades question

    I have a question regarding a practice problem I am trying to solve that I was wondering if someone was kind enough to help me gain insight in. ...

    Started by gameomega‎, 10-25-2012 06:56 AM
    • Replies: 0
    • Views: 1,790
    10-25-2012, 06:56 AM Go to last post
  4. Statistics - Comparing Dose Response Curves

    So I've got a stats question for anyone who can help; "You are testing the effects of a new drug that has been synthesized as an example of a...

    Started by PBnJams‎, 10-23-2012 02:21 AM
    • Replies: 4
    • Views: 9,578
    10-25-2012, 05:31 AM Go to last post
  5. Formula for Bonferroni vs Scheffe

    Hello, :) Do you need different formulas for Bonferroni? Or can you still calculate: F = SScontrast/MSerror MSerror = SSerror/dferror ...

    Started by krisstar‎, 10-24-2012 11:49 PM
    • Replies: 0
    • Views: 2,516
    10-24-2012, 11:49 PM Go to last post
  6. Lightbulb ANOVA or Kruskal Wallis

    Dear Stats experts here... I have a question: I am counting cells in histology slides of certain timepoints after a treatment. day 0, day...

    Started by med1234‎, 10-18-2012 04:02 PM
    anova, kruskal wallsi, non parametric, parametric
    • Replies: 13
    • Views: 4,335
    10-24-2012, 11:09 PM Go to last post
  7. How to find Z-value given probability?? PLEASE HELP

    Hi, I'm struggling on how to find the z value given the probability (working backwards using the table). Here's an example: The demand for a...

    Started by i.hate.stats‎, 10-24-2012 08:25 PM
    probability, statistics, z score, z value
    • Replies: 1
    • Views: 2,880
    10-24-2012, 08:48 PM Go to last post
  8. need to know number of product view to purchases I need to make a decision

    On my golf equipment website, if on average 1% of product views lead to a purchase, how many views do I need on a new product to determine if it is a...

    Started by ABCD‎, 10-15-2012 04:20 AM
    • Replies: 2
    • Views: 2,037
    10-24-2012, 07:30 PM Go to last post
  9. Testing for concordance

    An interviewer administered questionairre was carried out amongst twenty participants from a population of around 50. The requests were sent to all...

    Started by maltesedog‎, 10-24-2012 04:28 PM
    • Replies: 0
    • Views: 849
    10-24-2012, 04:28 PM Go to last post
  10. Simple regression vs Multiple regression - how to answer this question

    I am working on an assignment and stuck on whether I need to use a simple regression or a multiple regression. Any help would be appreciated. ...

    Started by klcna‎, 10-24-2012 02:34 PM
    correlations, multiple regression, simple regression
    • Replies: 1
    • Views: 1,194
    10-24-2012, 04:21 PM Go to last post
  11. Statistical Inference - Parameter Space

    "Suppose that (x_1, ... ,x_n) is a sample from a Bernoulli(\theta) distribution with \theta an element of unknown. We take the parameter space to...

    Started by simplemts‎, 10-24-2012 12:06 AM
    • Replies: 1
    • Views: 1,588
    10-24-2012, 08:05 AM Go to last post
  12. CDF questions.

    hi, given the pdf and cdf of 2 functions ( X,Y) --> bivariate AND the CDF of function X and Y seperately, is it possible to find the mean and...

    Started by mamypokozang‎, 10-24-2012 07:34 AM
    • Replies: 1
    • Views: 1,361
    10-24-2012, 07:53 AM Go to last post
  13. Scheirer-Ray-Hare test

    Hi, can I use a Scheirer-Ray-Hare test on an analysis where one factor has 2 levels and the other one 11?? A more general question would be can I use...

    Started by mousme‎, 10-24-2012 05:03 AM
    • Replies: 0
    • Views: 2,292
    10-24-2012, 05:03 AM Go to last post
  14. Deriving Formula from Ordinal Regression Results to Classify New Cases?

    What is the correct method for deriving a formula from the results of an Ordinal Regression, that can be used to predict the value of the dependent...

    Started by Vik_R‎, 10-24-2012 12:47 AM
    classification, ordinal regression
    • Replies: 0
    • Views: 986
    10-24-2012, 12:47 AM Go to last post
  15. Exponential Distribution

    Edit: Sorry, I realized after posting that my question didn't make sense as stated.

    Started by slacktide‎, 10-23-2012 11:00 PM
    • Replies: 0
    • Views: 1,191
    10-23-2012, 11:00 PM Go to last post
  16. Corresponding Standard Deviation Question HELP

    Stuck on this question from a practice test how do I go about solving this problem? A book collector has 12 copies of book A and 85 copies of book...

    Started by ruem‎, 10-23-2012 07:24 PM
    • Replies: 5
    • Views: 5,779
    10-23-2012, 10:05 PM Go to last post
  17. multivariate statistics help

    i'm currently stuck on a past paper question, you may find this as difficult as i am, but if you don't then please explain how to approach this,...

    Started by jamesforde123‎, 10-23-2012 08:55 PM
    • Replies: 0
    • Views: 1,336
    10-23-2012, 08:55 PM Go to last post
  18. Sports Stats Question

    Hello Talk Stats, I am a new member from Australia and was hoping you might be able to help a sports fan with something I have been musing...

    Started by nedkelly05‎, 11-11-2008 03:09 AM
    • Replies: 1
    • Views: 2,078
    10-23-2012, 05:49 PM Go to last post
  19. Meaning of bootstrapping residuals

    What does it physically mean when I bootstrap residuals in a regression problem. Like when I bootstrap residuals and create synthetic data does it...

    Started by houstonlife‎, 10-23-2012 01:52 PM
    bootstrapping, pairs, physical meaning, residuals
    • Replies: 1
    • Views: 1,165
    10-23-2012, 02:13 PM Go to last post
  20. Upside down and backward "e"

    What is the name of an upside down and backward "e"? Also, what does it stand for? I am looking over equations used in maximum likelihoods and keep...

    Started by hlsmith‎, 10-23-2012 12:48 PM
    • Replies: 6
    • Views: 5,502
    10-23-2012, 01:53 PM Go to last post
  21. Visualize and quantify factors that most contribute to customer decision

    To the Direct Marketing department I have to to visualize and quantify the factors that most contribute to a customer’s decision to buy any group of...

    Started by bgombas‎, 10-23-2012 05:58 AM
    factor analysis, spss
    • Replies: 8
    • Views: 1,430
    10-23-2012, 09:34 AM Go to last post
  22. Identify group based on sales

    Hi all, I need a little advice from your expertise... I have a pool of data which contains a list of stores and their sales quantity for 4...

    Started by henrygd‎, 10-11-2012 09:14 AM
    • Replies: 5
    • Views: 1,283
    10-23-2012, 09:21 AM Go to last post
  23. Finding percentile

    Hi everyone, a lot of questions asked on here was about finding a certain precintile, but my question asks to find the precintile. The only...

    Started by Zannie‎, 10-22-2012 07:34 PM
    • Replies: 1
    • Views: 1,307
    10-22-2012, 07:40 PM Go to last post
  24. Predictive Model: how to solve multivariate problem

    If there are 4 variables with differing R-squares, how do you assign a weighting to each? Example (R-squared) (Projected Estimate) (Weight)...

    Started by gschmilinsky‎, 10-22-2012 12:54 PM
    • Replies: 6
    • Views: 2,279
    10-22-2012, 07:20 PM Go to last post
  25. Independence of three normal distributions

    Hi everyone, I'm analyzing some data from a fishing gear experiment. The gear diverts some fish away from the net, so the response variable here...

    Started by AFH‎, 10-18-2012 12:26 PM
    • Replies: 6
    • Views: 1,569
    10-22-2012, 05:25 PM Go to last post
  26. I don't get this question at all

    So my teacher gave us practice questions for a test review and i dont understand these questions at ALL. Can someone please explain how to do...

    Started by Biz‎, 10-22-2012 10:45 AM
    • Replies: 1
    • Views: 2,122
    10-22-2012, 12:15 PM Go to last post
  27. How to compare more than 2 percentages

    Hi, I want to compare percentage mortality of 4 groups of treatment of my specimens. Which test should i used? I know that i can use chi square...

    Started by hianghao‎, 10-22-2012 09:40 AM
    • Replies: 0
    • Views: 1,292
    10-22-2012, 09:40 AM Go to last post
  28. Small population statistics - importance rankings

    We are dealing with 20 responses - (population is 50 and was all targeted). We have some questions which required the participants to assign how...

    Started by maltesedog‎, 10-22-2012 09:10 AM
    • Replies: 0
    • Views: 1,496
    10-22-2012, 09:10 AM Go to last post
  29. Repeated measure ANOVA or mixed effects model?

    Hi everyone, my goal is to understand whether a treatment modify the duration of the calls of a bird. I found not a similar situation in the...

    Started by Ornitho‎, 10-19-2012 03:26 AM
    • Replies: 3
    • Views: 2,253
    10-22-2012, 02:57 AM Go to last post
  30. Skewness and non-normally distributed data - Question.

    Hello everyone, this is actually my first post as I have just discovered this amazing forum for talking about statistics. I've read through the...

    Started by PBnJams‎, 10-11-2012 08:43 PM
    • Replies: 9
    • Views: 4,104
    10-21-2012, 09:01 PM Go to last post
  31. Interpretation of low, negative, cubic clustering criterion values

    Hello all, My question is how do you use the cubic clustering criterion to assist in selecting an appropriate number of clusters when the values...

    Started by kwak123‎, 10-21-2012 08:41 PM
    ccc, cluster analysis, clusters, cubic clustering, interpretation
    • Replies: 0
    • Views: 5,370
    10-21-2012, 08:41 PM Go to last post
  32. Light bulbs problem


    Started by alphaville‎, 10-21-2012 12:31 PM
    • Replies: 0
    • Views: 1,542
    10-21-2012, 12:31 PM Go to last post
  33. Calculating Partial Eta Squared from Wilk's Lambda

    Hello! I am doing homework for my multivariate stats class. Our teacher is asking us to calculate the partial eta squared using wilks lambda. The...

    Started by steph88‎, 10-20-2012 09:12 PM
    partial eta squared, wilk's lambda
    • Replies: 0
    • Views: 5,168
    10-20-2012, 09:12 PM Go to last post
  34. Hypothesis Testing - finding the power and beta!

    A medicine dispensing machine is designed to discharge on average at least 8ml of medicine per dose with a standard deviation of 0.2ml. The amount of...

    Started by GirlyEmmie‎, 10-20-2012 08:00 PM
    beta, hypothesis testing
    • Replies: 0
    • Views: 1,599
    10-20-2012, 08:00 PM Go to last post
  35. Odds Ratio vs Risk Ratio vs Relative Risk

    I've conducted a risk factor analysis (for a type of injury) upon a prospective cohort. Part of this involved a chi-square analysis upon predictor...

    Started by Rekansha‎, 10-20-2012 07:20 PM
    • Replies: 0
    • Views: 1,715
    10-20-2012, 07:20 PM Go to last post
  36. Running a T-Test when you don't have mean/STDev

    Hey guys, I'm currently enrolled in a statistics course right now that deals with Quality Improvement methods. The previous course acquainted us...

    Started by renaissanceman87‎, 10-18-2012 04:26 PM
    • Replies: 5
    • Views: 1,722
    10-19-2012, 12:04 PM Go to last post
  37. Process Control Measures - Valid Approach?

    I am about to start an exercise in Control Measurement and would appreciate validation of the proposed approach and data grouping. The object of the...

    Started by etb‎, 10-19-2012 08:52 AM
    • Replies: 0
    • Views: 1,402
    10-19-2012, 08:52 AM Go to last post
  38. Normal Conditional Distribution

    Anyone know answer to below. If two random variables X and Y are both marginally normal, and conditional distribution of Y given any value of X is...

    Started by learner928‎, 10-19-2012 12:22 AM
    • Replies: 4
    • Views: 1,408
    10-19-2012, 07:53 AM Go to last post
  39. Using Hypothesis test for decision making - find if sample represents the population

    Hi All, I work with an NGO and we have a telemarketing department which purchases phone number databases for calling and marketing our cause. We...

    Started by shivapps‎, 10-18-2012 12:12 AM
    • Replies: 7
    • Views: 2,726
    10-19-2012, 05:44 AM Go to last post
  40. Smile How to workout the multiple comparison of means using common SED or SEM after ANOVA?

    Hi, good day all. I have a problem here. I am doing an obesity research on 4 groups of mice. Each group contains 8 mice (n=8) I receive a...

    Started by darrengouk‎, 10-19-2012 04:21 AM
    • Replies: 0
    • Views: 1,430
    10-19-2012, 04:21 AM Go to last post
  41. Smile Comparing this year's sales to last year's sales form a panel of pharmacies.

    Hello I have sales of a product,by month, for February to August 2011 and the same period for 2012. The sales are from a panel of 500 pharmacies...

    Started by JKS‎, 10-18-2012 05:11 PM
    • Replies: 1
    • Views: 1,572
    10-19-2012, 03:07 AM Go to last post
  42. ROC curve help

    Hi!, im new at spss, and dont know much about statistics in general... I have a group of ppl that answered the same questioner twice, but with a...

    Started by kmpkmp‎, 10-11-2012 02:57 PM
    • Replies: 1
    • Views: 971
    10-18-2012, 10:08 PM Go to last post
  43. Survey Data analysis

    Hi, I have a survey data that measures the conditions/noise levels and 3 other areas at the workplace(total of 5 areas).These are in turn used to...

    Started by vineshgaonkar‎, 10-18-2012 10:04 PM
    statistics, survey data
    • Replies: 0
    • Views: 880
    10-18-2012, 10:04 PM Go to last post
  44. Think my brain may explode!

    Hi there, I have tried my best to answer this question myself, have read several text books and online support, and for some reason I am just not...

    Started by JMH11‎, 10-18-2012 05:11 PM
    • Replies: 0
    • Views: 1,395
    10-18-2012, 05:11 PM Go to last post
  45. 76 percent per 1,000 women aged 15-19, U.S

    Hello everyone, I am mathematically and statically challenged beyond belief. So, please riddle me this: If you look at the first paragraph of...

    Started by Naviva‎, 10-18-2012 10:30 AM
    • Replies: 4
    • Views: 1,598
    10-18-2012, 03:12 PM Go to last post
  46. Who is more likely to win (mean score + standard deviation)

    My teacher gave this as an example: "Scotland is going to play vs Tonga in rugby. Tonga has a mean score of 18 and a standard deviation of 13....

    Started by GardR‎, 10-18-2012 07:52 AM
    • Replies: 11
    • Views: 2,710
    10-18-2012, 02:09 PM Go to last post
  47. Distributions of random variables

    I have been sweating over these problems for 4 hours - can someone please help? Let Z1,...,Zn be identically independently distributed ~N(0,1)...

    Started by marleygrace‎, 10-18-2012 12:45 PM
    • Replies: 9
    • Views: 1,870
    10-18-2012, 01:24 PM Go to last post
  48. Question

    Student A scored a 90 on her Statistics test (M = 87, SD = 6). Student B scored a 90 on his composition test (M = 88, SD = 3). Which student did...

    Started by notastatmaster‎, 10-18-2012 09:56 AM
    • Replies: 4
    • Views: 1,621
    10-18-2012, 10:09 AM Go to last post
  49. Conditional probability question ~ why is P(H) = P(HH)+P(HT)?

    Hi, I am told that the probability of an unfair coin is the following: P(HH) = 4/9 P(HT) = 1/9 I need to find what the probability of...

    Started by gameomega‎, 10-18-2012 01:10 AM
    • Replies: 2
    • Views: 1,364
    10-18-2012, 03:54 AM Go to last post
  50. experiment: estimating candies in a jar

    this is an experiment project for my class. there is a big jar filled with 2 types of candies. we need to estimate 3 things: A. how many Type A...

    Started by iniesta13‎, 10-16-2012 08:39 PM
    • Replies: 0
    • Views: 1,457
    10-16-2012, 08:39 PM Go to last post
  51. Question Comparison of ordinal data - same subjects, same questions, 5 years later

    Hi all, I'm looking for a good way to represent changes in ordinal-type data. I have 2 sets of data. In the first set, 50 companies (which...

    Started by ajvar‎, 10-16-2012 03:23 PM
    • Replies: 0
    • Views: 1,712
    10-16-2012, 03:23 PM Go to last post
  52. Two-Way ANOVA question

    Hey guys I'm new to this form. I've had trouble with stats over the past three years. I'm fourth year university and only need this one statistics...

    Started by mattpeters1‎, 10-16-2012 03:00 PM
    • Replies: 0
    • Views: 3,520
    10-16-2012, 03:00 PM Go to last post
  53. Compare Treatment Effects of 2 Groups - Repeated Measures & Binary Outcome

    Hi, I have two groups (1:non-comorbid group, 2:comorbid group), where patients in one group have a condition that patients in the other group do...

    Started by okie1125‎, 10-16-2012 01:50 PM
    binary outcome, longitudinal, repeated measures
    • Replies: 0
    • Views: 2,720
    10-16-2012, 01:50 PM Go to last post
  54. Using regressions in monte carlo simulations

    Hey Guys, I'm building a valuation model with monte carlo and regression elements but could use a bit of help. The model breaks down the...

    Started by Bokononblue22‎, 10-16-2012 09:39 AM
    heteroscedasticity, monte carlo, regression coefficient
    • Replies: 0
    • Views: 1,242
    10-16-2012, 09:39 AM Go to last post
  55. Simulation of unlikely events over random binary variables knowing their probability

    Hi, I have n binary variables all having the same probability p of flipping. Probability is low, so I wouldn't want to go through generating a...

    Started by stanmoon‎, 10-16-2012 01:44 AM
    expectancy, random, simulation, variance
    • Replies: 3
    • Views: 2,171
    10-16-2012, 03:27 AM Go to last post
  56. Please Help - How Do I Prove Hypothesis?

    Hi, I am in 6th grade, trying to do an analysis of data for a science fair project. Sorry, but I am only at Algebra 1, I do not have any...

    Started by Sci‎, 10-15-2012 10:40 AM
    anova, help please, null hypothesis, prove data
    • Replies: 12
    • Views: 3,040
    10-15-2012, 06:50 PM Go to last post
  57. A bit confused on confidence intervals

    Why does the t-value for the 98% confidence interval increase to 2.33 from 1.96? Basically what determines these values and what does it mean?

    Started by 1in10croak‎, 10-14-2012 10:06 PM
    • Replies: 3
    • Views: 1,752
    10-15-2012, 03:19 PM Go to last post
  58. How can i determine which predicted value is more accurate?

    Hey everyone, So i did a simple linear regression on the data below: Assigned questions: (c) Predict the heart disease mortality...

    Started by KingJames‎, 10-08-2012 09:39 PM
    • Replies: 4
    • Views: 2,726
    10-15-2012, 02:33 AM Go to last post
  59. Quick Q

    How would I calculate a sample mean if I'm given the standard deviation and sample size? The example in the book says "The volume of liquid in a...

    Started by katcity‎, 10-14-2012 09:22 PM
    • Replies: 1
    • Views: 1,210
    10-14-2012, 11:31 PM Go to last post
  60. Calculating the residual?

    Hello, Based on the attached picture, I am supposed to calculate B1(hat) and B0(hat), which I have done successfully. B1(hat) = 0.451 and...

    Started by Walowizard‎, 10-14-2012 08:42 PM
    • Replies: 7
    • Views: 2,406
    10-14-2012, 10:26 PM Go to last post

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