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Forum: Statistics

Statistics course and homework discussion. Elementary statistics.

1. 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...

• Replies: 1
• Views: 196,968
07-16-2014, 11:01 AM
2. 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: 66,862
09-30-2005, 09:44 AM
1. repeated mesures with negative correlation

Hi all I'm a data analyst at the University of Sydney, Australia doing research into home advantage in soccer. I am using Poisson regression to...

• Replies: 0
• Views: 2,036
09-22-2012, 10:01 PM
2. Summation Problem - new in the forum

Hello everyone, I am new in the forum and I came here because I am desperate. I am taking stats 1101 in school not because I chose to, but because I...

• Replies: 3
• Views: 1,573
09-22-2012, 03:36 PM
3. Quick IV/DV Question

Hi everyone, Ive got a quick question on variable types. In my study, people watch a clip, then answer how they feel between 1 and 10. Then they...

• Replies: 0
• Views: 1,279
09-22-2012, 01:15 PM
4. R question

Any suggestions to find a formula relating R-square and the F-test for regression.

• Replies: 7
• Views: 3,077
09-22-2012, 09:21 AM
5. Error Propagation

If I have two sets of measurements (x and y) each with 3 values x: 1,2,3 and y: 4,5,6 and I need to divide the two x/y to get z can I work out all...

• Replies: 0
• Views: 1,060
09-21-2012, 08:57 PM
6. Post Hoc testing for ANCOVA

Hi everyone. I am trying to figure out what post hoc tests are most appropriate for an ANCOVA with two IVs and two Covariates where one IV may act as...

• Replies: 0
• Views: 1,191
09-21-2012, 04:26 PM
7. Likert scale data and regression

First I know that in theory the independent variables don't assume any given distribution. But in fact that can't be true or you would use...

• Replies: 16
• Views: 5,434
09-21-2012, 04:11 PM
8. Probability or statistical expected average: How to determine a success or failure?!

Hey, (I am a NOOB in statistics) I am trying to determine whether my experiment results indicate a success or just turns out as it would have...

• Replies: 1
• Views: 1,282
09-21-2012, 08:08 AM
9. Which paired test?

Hi, I have a little slightly complicated analysis which I want do describe in form of another similar but clearer example: I have 15 different...

• Replies: 1
• Views: 1,154
09-21-2012, 02:45 AM
10. Standardized Value Issues

Hello talkstats! So I took a test the other day and didn't do so well. I'm trying to go over the test now with a partner and neither of us can...

• Replies: 0
• Views: 1,477
09-20-2012, 07:30 PM
11. Converting historical amounts of currency to other currencies in real terms.

Hi guys, nice to be here. im analysing government expenditure and one of the sources ive used has calculated the expenditure 1995 up to 2009...

• Replies: 0
• Views: 1,556
09-20-2012, 01:33 PM
12. How best to display Dprimes scores using bar graph

moved to Psychology Statistics forum section...

• Replies: 0
• Views: 1,323
09-20-2012, 06:38 AM
13. Percentile of SAMPLE mean

Can someone please explain to me how to work out the percentile of the sample mean (diff to confidence intervals which is pop mean) The Q is: ...

• Replies: 8
• Views: 16,747
09-20-2012, 04:52 AM
14. Would my calcuation of the expectation of an expoentitated random variable work? HELP

Hi, I am trying to find the expectation of a random variable X defined as the following: Xi = 1 or -1. with P(X=1) = 0.5 and P(X=-1) = 0.5 ...

• Replies: 1
• Views: 1,458
09-20-2012, 01:26 AM
15. Need Help with hw problem

Derive the formula for the variance of Y-hat. Show at least two steps. I know I am looking for Var(b0 hat + B1hatXo) I just don't know how to get...

• Replies: 0
• Views: 1,063
09-19-2012, 10:17 PM
16. Looking for help! which software to use??

Hi Guys, I have a small amount of experience using SPSS and am currently using this for some work on statistical analysis of sports injuries in a...

• Replies: 4
• Views: 1,330
09-19-2012, 08:11 PM
17. help with anova/manova/ancova???

Hello, I'm a first time poster, please excuse my long-winded question! I am trying to analyze the results of my experiment which is set up as...

• Replies: 0
• Views: 1,554
09-19-2012, 07:13 PM
18. IRT question

I am not sure item response theory is statistics as defined here or not:shakehead but I have a question to correct on my comps that I have been...

• Replies: 15
• Views: 4,141
09-19-2012, 03:11 PM
19. How to prove that microbiological growth curves significant differ from each other?

Hello everyone, A while ago I innoculated 3 pieces of the same chocolate each with another bacterial culture (every time in the same...

• Replies: 1
• Views: 1,464
09-19-2012, 10:12 AM
20. how to calculate adjusted standard error to report with adjusted means for ancova

How to calculate adjusted mean and adjusted std error? I'm using regression as ancova in R as below. Condition is coded: 0 = control, and 1 =...

• Replies: 0
• Views: 3,513
09-19-2012, 10:07 AM
21. Multiple Regression Number of Variables and Predictors?

Hi Could someone please help me with this question I've been staring at my textbook for hours and it doesn't explain how to find no of variable or...

• Replies: 1
• Views: 3,488
09-19-2012, 03:29 AM
22. Binomial pdf and estimator

The following is the problem: Five hundred adults are asked whether they favor a bipartisan campaign finance reform bill. If the true proportion...

• Replies: 1
• Views: 2,796
BGM
09-19-2012, 02:32 AM
23. Correlation of means

How comes that two variables positively correlated in levels are negatively correlated in mean? That is: let x, y be two observed variables and X^,...

• Replies: 2
• Views: 1,007
09-19-2012, 12:31 AM
24. Effect size for robust ANOVA?

Hi - I am using one-way ANOVA but there is violation of homogeneity of variances (tested using Levene's statistic) and unequal group sizes. ...

• Replies: 2
• Views: 3,831
09-18-2012, 02:29 PM
25. What hypothesis is regression intercept-only model testing?

In a regression model without any predictors, the intercept is subject to a hypothesis test. For example: summary((lm(mpg~1, data = mtcars))) ...

• Replies: 2
• Views: 6,435
09-18-2012, 07:59 AM
26. Help on analysis of variance

I have tested ventilators performances on a lung model. I have tested 5 differents ventilators models. I have tested 3 different machines for each...

• Replies: 1
• Views: 1,425
09-18-2012, 04:22 AM
27. Non-factorial ANOVA?

Here's my design: Each participant is trained to discriminate 2 categories in each of 2 domains. In one of the domains, they receive training...

• Replies: 0
• Views: 1,504
09-17-2012, 09:23 PM
28. Economic Significance

Hi guys, Currently I am doing a research about elimination of etfs. Now I have to run a logistic regression using stata. However, I read somewhere...

• Replies: 4
• Views: 4,120
09-17-2012, 01:28 PM
29. Bonferroni-Holm correction for Psychology

Hi All, I was hoping someone could explain to me, in the simplest language possible, what a Bonferroni-Holm correction is, why and under what...

• Replies: 2
• Views: 1,849
09-17-2012, 09:24 AM
30. Using multiple P-values

I have a number of p-values from permutation tests I've done on my data. One p-value for each recording. Can I compile these values to test for...

• Replies: 1
• Views: 1,285
09-17-2012, 07:34 AM
31. Medical Statistic - Help a Surgeon out!

Ok here's your chance, yes your smarter. I have tried to calculate my own p-value for some clinical research. Can't do it. I can operate on your...

• Replies: 0
• Views: 1,163
09-16-2012, 11:44 PM
32. HELP!!! Chi-Square Tests

What is the difference between Homogeneity of proportions across two or more groups, Test of independence, and Goodness of fit test? Also, how...

• Replies: 0
• Views: 867
09-16-2012, 08:41 PM
33. Linear independence

I'm used to the following definition of linear independence: a family of vectors is linearly independent if none of them can be written as a linear...

• Replies: 0
• Views: 1,229
09-16-2012, 04:10 PM
34. Cronbach's alpha

Hi everyone, I am trying to quantify the rater-reliability for a test with three judges and two output alternatives. From what I have read this...

• Replies: 0
• Views: 929
09-16-2012, 02:10 PM
35. statistical correlation

Years ago I saw an 'interesting' set of data. The data presented an analysis of stock market (NYSE) performance versus an unnamed variable, x. The...

• Replies: 0
• Views: 1,240
09-15-2012, 11:34 PM
36. Interpreting glm results

Hi guys, I've performed my first ever glm (proud moment!) However.... I haven't a clue what the results mean Can someone please help me...

• Replies: 5
• Views: 3,515
09-15-2012, 06:10 AM
37. Normal Distribution and Grade Cut-offs

Hello, I tried googling this question, watching how-to videos, and read over the chapter in my textbook several times but I cannot seem to understand...

• Replies: 6
• Views: 3,018
09-14-2012, 04:47 PM
38. Will one-way ANOVA and Tukey HSD work?

Hi all. This isn't a homework problem, but one I'm encountering at work. The experiment goes like this: We have 4 animals. Cells from each animal...

• Replies: 2
• Views: 1,600
09-14-2012, 04:06 PM
39. [SOLVED] Assumptions of an ANOVA

1. I could google this but in my past searches I get conflicting stuff and wrong stuff. So I'll state what I think are the assumptions of ANOVA &...

• Replies: 4
• Views: 1,744
09-14-2012, 01:02 AM
40. kurtosis and nongaussian

Hi, all I am looking into kurtosis of random variables. As far as I know, kurtosis for gaussian random variables is zero, and for most of...

• Replies: 2
• Views: 1,993
09-13-2012, 07:00 PM
41. How many measurements needed to distingish between two outcomes?

I have a historical dataset of about 500 measurements. Datapoints that turned out to indicate A or B, each have a distribution from which I computed...

• Replies: 2
• Views: 1,350
09-13-2012, 04:41 PM
42. Multinomial Logistic Regression

Hello, I am planning to run a logistic regression and I need some help if you can. So I have a IV for example family income. I needed to divide it...

• Replies: 2
• Views: 1,177
09-13-2012, 03:17 AM
43. hypothesis

Thanks for you help...can you help me with other 5 questions too?? Q1.A significance test gives a p-value of 0.04 when testing a null hypothesis....

• Replies: 2
• Views: 1,816
09-12-2012, 04:48 PM
44. a problem regarding maximum and minimum of two positive random variables

Suppose X and Y are two positive random numbers. Define U = max(X, Y ) and V = min(X, Y ) Show that: (a) E(X)E(Y ) >= E(U)E(V ): (b) Var(X) +...

• Replies: 1
• Views: 1,240
09-12-2012, 11:41 AM
45. hypothesis testing

Hi I need some help with questions from prevous exam..they dont have answers can anyone help please? Q1. A significance test was performed to...

• Replies: 3
• Views: 4,737
09-12-2012, 11:34 AM
46. Simple simulation problem!

Hi, I have a problem that will probably be very simple for the experts on this forum. I don't have any statistical background, so this is a bit too...

• Replies: 13
• Views: 1,799
09-12-2012, 09:57 AM
47. differences between frequencies

Dear all, I'm trying to figure out how to best determine if there is a significant differences between how often a particular answer to a question...

• Replies: 26
• Views: 4,434
09-12-2012, 03:41 AM
48. compare questionnaire responses of parents

Hi all, I have a question with regard to comparing the responses of parents to a questionnaire on the home environment. The questionnaire is a set...

• Replies: 1
• Views: 957
09-12-2012, 03:06 AM
49. Food & Drug Administration (US) statistical regulations

Hello, I want to know if there is anyone who knows about FDA regulations to do statistical tests? Or if anyone has a document about it?

• Replies: 0
• Views: 883
09-12-2012, 01:42 AM
50. Combinatorics Question

I'm having a very tough time solving a problem for my probability class. Any help would be appreciated. Here's the problem: Your statistics...

• Replies: 6
• Views: 2,997
09-11-2012, 09:42 PM
51. Find Outliers in Transaction Data

Hi folks, I'm looking for your opinions on the best way to solve a need I have for finding outliers in a set of data. A while ago I wrote a...

• Replies: 0
• Views: 2,835
DVC
09-11-2012, 02:23 PM
52. Observed Test Equating

Hi All, I run a quantitative Special Interest Group which has bi-monthly seminars. The most recent was an excellent one on observed test equating...

• Replies: 0
• Views: 1,168
09-11-2012, 01:33 AM
53. Mediation with Structural Equation Modeling....

First...Hello! My question is about how to test mediation with structural equation modeling. I know there is a way to test mediation with regression...

• Replies: 0
• Views: 2,450
09-10-2012, 01:47 PM
54. Likert Scale, basic tests

Hello I have collected data using a questionnaire for the following a) Role played by a person b) years of experience c) type of work done ...

• Replies: 3
• Views: 2,337
09-10-2012, 10:00 AM
55. Mann Whitney u test- Interpretation help?

Hi I have conducted a Mann Whitney u test to test to see if there is a difference between one of my variables and gender. The test shows there is...

• Replies: 3
• Views: 8,187
09-10-2012, 02:45 AM

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