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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: 196,581
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: 66,632
09-30-2005, 09:44 AM
1. ### Rates vs Percentage

What is the rule of thumb for when to report a rate vs. a percentage? For example, if you want to show trends from year to year in the...

• Replies: 1
• Views: 25,716
09-09-2010, 12:49 PM
2. ### VERY BASIC QUESTION- T-test in R

I am currently working as a teaching assistant, and I have to teach a lab next week in which the students run a paired T-test using R. I have never...

• Replies: 1
• Views: 4,458
09-09-2010, 11:03 AM
3. ### Best test to use for comparing detection rates?

Hi, I am a total newbie in stats and my current project met with a speed-bump... My project involves evaluating 3 different methods to detect...

• Replies: 3
• Views: 4,189
09-09-2010, 07:04 AM
4. ### Post hoc tests for a mixed 2 X 3 X 3 X 2 ANOVA

Hi there I would be eternally grateful for any assistance with the following query. I am in the process of analysing some results for my MSc...

• Replies: 0
• Views: 3,785
09-08-2010, 03:56 PM
5. ### Help

Is there any body can help me in data analysis and result interpretation? I'll pay for that job as it is very necessary to finish my research...

• Replies: 4
• Views: 3,466
09-08-2010, 11:16 AM
6. ### a quick stats questions about p and F/t values

Hi, I am pretty new to stats and am doing a heap of F-tests and t-tests. i was under the impression that when the calculated value (F or t) was...

• Replies: 1
• Views: 2,800
09-08-2010, 09:52 AM
7. ### Profit probability

Is there any way that I can determine a level of confidence (preferably using Excel) that a particulal betting system might prove profitable? ...

• Replies: 3
• Views: 3,988
09-08-2010, 06:46 AM
8. ### Conditional Probabiltiy

Hey, I'm trying to evaluate a conditional probability and I'm not able to figure it out. It's fairly simple: two random variables, both Normal with...

• Replies: 2
• Views: 1,862
09-07-2010, 04:06 PM
9. ### Basic Time Series Question Regarding Transformations

This question is regarding a time series problem using the classical decomposition model Xt=Tt+St+Nt After a log transformation to the data, I am...

• Replies: 2
• Views: 2,031
09-07-2010, 12:33 PM
10. ### Regression Model with scaled intercept

I'm using the following OLS-regression model: Y = a + b1*X1 + b2*X2 + e Now all of the variables in my sample get scaled (by ta), so that: ...

• Replies: 0
• Views: 3,307
09-07-2010, 11:01 AM
11. ### interpreting linear and curvilinear effect

hi! I'm testing linear and curviliear effects of one continuous IV in another continuos DV. I've centered the IV (IVc) and squared it (IVcsq)...

• Replies: 0
• Views: 5,156
09-07-2010, 05:21 AM
12. ### Interaction and Main effect

Hi, I have one general question. I want to know whether I need to add an interaction term. Let's say I have two categorical variables (X & Y)...

• Replies: 1
• Views: 4,289
09-06-2010, 05:51 PM
13. ### Logistic Regression Output

Hi, I have done a logistic regression but am having trouble interpreting the output. I looked at the effect of three vegetation types (H M L) and...

• Replies: 5
• Views: 7,237
09-06-2010, 02:57 PM
14. ### Hypothesis Testing for Paired Sample

In hypothesis testing of means for paired sample,why do we have only t test ? why don't we have similar z test?

• Replies: 5
• Views: 3,467
09-06-2010, 02:13 PM
15. ### Compare means between groups

Hi, I am currently writing my master thesis in finance and have a question of pretty basic nature. I would be very grateful if someone could help...

• Replies: 6
• Views: 6,282
09-06-2010, 06:24 AM
16. ### Missing values

On the basis of the partially completed contingency table below, select all the true statements from the following list: (note that the given...

• Replies: 11
• Views: 6,974
09-05-2010, 04:08 PM
17. ### Poisson distribution

Hi I am new to this but I wonder if anyone can help. I have a data set for number of insects caught in different habitats and have been analysing...

• Replies: 3
• Views: 6,100
09-05-2010, 06:00 AM
18. ### Which tests to use?

Hi, I am conducting research comparing child anxiety type (anxious vs non-anxious) on their parents' parenting style (5 styles), to see if anxious...

• Replies: 1
• Views: 2,496
09-03-2010, 08:16 PM
19. ### Cohen's d for within-design

I am having problems in understanding and calculating the effect size for the following conditions. Basically I have 13 subjects and a within...

• Replies: 1
• Views: 6,872
09-03-2010, 04:24 PM
20. ### Can't decide on statistical test...

I really am stumped. I can do most statistical tests myself, but I can't for the life of me work out which test to use on this occasion. I have...

• Replies: 5
• Views: 3,396
09-03-2010, 12:48 PM
21. ### Don't Know where to start!!

Hey Everyone!! I hope someone can help me with this. I have data that was collect a year ago on a weight lose study. The sample size is 8...

• Replies: 6
• Views: 3,581
09-03-2010, 09:14 AM
22. ### Help with a pilot cohort study sample size estimation

Hi everyone, I am a new research student and I am struggling now. Please can anyone advise me on sample size required for my project? I am...

• Replies: 4
• Views: 8,082
09-02-2010, 06:18 PM
23. ### Margin of Error - Confidence Level

I sent out a questionnaire to hundreds of people and recieved 154 responses. Some of the questions have a yes/no answer. So for one of them I...

• Replies: 12
• Views: 6,269
09-02-2010, 03:51 PM
24. ### A Medical Imaging statistics Question

Hi, I did a training project a work a while ago and I never found a satisfactory answer to a inferential statistics problem. This question might...

• Replies: 1
• Views: 2,830
09-02-2010, 11:03 AM
25. ### Estimating type 1 error post-hoc VS post-hoc samples size calculation

Hi, I have completed a small randomized clinical trial where I surprisingly observed a statistically significant survival (p=0.02) benefit with a...

• Replies: 0
• Views: 5,029
09-02-2010, 04:49 AM
26. ### Linear regression question

For F, i find x is 11.5 then to calculate the CI we're given this formula for question it's then we use that SDx and times it by the tcrit for...

• Replies: 0
• Views: 2,201
09-02-2010, 02:38 AM
27. ### independent t test

i have two variables: one the age and the dependent variable is stress age is normaly distributed the outcome or deprndent variable stress is...

• Replies: 5
• Views: 4,572
09-01-2010, 02:10 AM
28. ### Proportion receiving a treatment

Dear all, thank you for taking the time to answer I'm wondering whether I have the right method to compare 4 proportions: Group, Treated, ...

• Replies: 0
• Views: 1,827
08-31-2010, 11:25 AM
29. ### Make survey to find trends

Good afternoon, Thank you for reading my thread. I am making a very exciting study of what makes people attractive. My background is as a...

• Replies: 0
• Views: 2,572
08-31-2010, 10:14 AM
30. ### Scheffe critical value question (easy)

A researcher collects data about the efficacy of a new medication for ADHD in the context of an existing medication, a placebo, and no treatment. She...

• Replies: 2
• Views: 8,407
08-30-2010, 10:37 PM
31. ### Fair Coin... Chi square or binomial?

Hello all, this is my first post, so please be gentle with me. When testing whether a coin is fair or not, is it correct to use the binomial...

• Replies: 7
• Views: 18,468
08-29-2010, 01:24 PM
32. ### We need help with hypothesis testing for a difference between proportions

Essentially we are looking at a study of a group of 34 facilities--17 type A facilities and 17 type B facilities. Using one measure, 6 of the 17 type...

• Replies: 5
• Views: 4,698
08-28-2010, 08:46 PM
33. ### T-test on house prices

I'm carrying out research into whether the implementation of a transport system has resulted in a price rise in property values. I have two groups...

• Replies: 2
• Views: 2,514
08-28-2010, 03:11 AM
34. ### Distributions

Let Z1,.....Z6 be a random sample of six observations from the N(0,1) distribution, and let: Z bar = 1/6(summation from 1 to 6) of Zi and S^2 =...

• Replies: 4
• Views: 3,856
08-27-2010, 09:39 PM
35. ### Statistics question, can you help?

I am doing a university course and it is divided into to two parts, assignments (65%) and exam (35%). If I was to get a B average (75%/100) for my...

• Replies: 1
• Views: 2,452
08-27-2010, 06:59 PM
36. ### Correspondence Analysis: Lowest cell frequency?

Dear All, First of all I would like to thank those of you who suggested that I could use CA for my research on elections in December last year. It...

• Replies: 0
• Views: 1,847
SAJ
08-27-2010, 03:04 AM
37. ### Categories with 1 or two respondents

i have to see if there is association between the out come and some variables i convert them to catigories like the country of origin i have 4...

• Replies: 0
• Views: 2,129
08-26-2010, 10:34 PM
38. ### Time series - autoregressive and autocorrelation models

anyone using this text : http://www.amazon.com/Second-Course-Statistics-Regression-Analysis/dp/0130223239 I am quite confused with...

• Replies: 1
• Views: 5,328
08-26-2010, 12:54 PM
39. ### age and Mann-Whitney test

urgent question, i have the age variable not normaly ditrrebuted and i wanted to explore its association with the outcome (not case , case) at...

• Replies: 1
• Views: 3,921
08-26-2010, 09:50 AM
40. ### expected B

is (the expected B) that appear in logestic regression is the same as odds ratio? is it the adjusted odds ratio?? please make it clear to me

• Replies: 2
• Views: 3,573
08-26-2010, 01:54 AM
41. ### False Discovery Rate (FDR)

Hi Guys, I have been asked to use the FDR instead of Bonferroni. Unfortunately I have never heard of it. Any ideas please? Thanks Ali

• Replies: 0
• Views: 2,071
08-25-2010, 04:33 PM
42. ### Test for non-normal, non-independent samples

The situation... I want to determine whether the "average \$ per mailed customer" (to a direct mail appeal) is statistically different for Group A...

• Replies: 2
• Views: 2,890
08-25-2010, 04:20 PM
43. ### er? only 4 choices in dependable variable?

Hi guys, Doing a bit of work for Uni which requires some statistics. In the past I have carried out different tests however after some...

• Replies: 0
• Views: 1,945
08-25-2010, 02:32 PM
44. ### How to treat 'over the years' data during regression

Hi, I have a dataset which has values for variables for each company for six different years. What data should I use for doing regression and...

• Replies: 1
• Views: 1,957
08-25-2010, 12:56 PM
45. ### Confidence interval

The experimenter who collected these data wants to take another sample in order to find a 99% confidence interval for μ that is 3 units wide. Use...

• Replies: 2
• Views: 3,078
08-25-2010, 10:00 AM
46. ### mann withney test

i have used a copying scale, that ask about 14 coping styles .. the questions are likert type. since the distribution of the responces was not...

• Replies: 5
• Views: 4,225
08-25-2010, 02:43 AM
47. ### Correlation b/t categorical and continuous variables

Lets say that I have a continuous variable, such as height in inches. I also have a 3-value categorical variable for height, such as short, average,...

• Replies: 1
• Views: 6,044
08-24-2010, 05:32 PM
48. ### Zero in cell for Fisher's Exact?

Good evening, I finally figured out how to get my version of SPSS to report Fisher's Exact numbers...that took several days! Most places on the...

• Replies: 0
• Views: 7,110
08-23-2010, 09:43 PM
49. ### Experiments and replicates

Hi all. The experiment: I treat a substrate "S" with different concentrations of factor "A" and observe the effect on factor "B". In one...

• Replies: 2
• Views: 3,278
08-23-2010, 03:10 PM
50. ### Need help on these Stat questions I missed on my test.

If the graph is skewed to the right what is bigger, the mean or median? A set of data is found to have a sample standard deviation of 25. Suppose...

• Replies: 3
• Views: 3,318
08-23-2010, 02:16 PM
51. ### Four-Way ANOVA

Hello, I want to analyse the effects of four categorical independent variables on one dependnet variable. For each independent variable, I have two...

• Replies: 0
• Views: 4,161
08-23-2010, 01:47 PM
52. ### Contrasts - reporting results

Are contrast conclusions supposed to include the mean score of each group and the mean difference? Or just one? How do you properly report the mean...

• Replies: 0
• Views: 6,588
08-23-2010, 09:20 AM
53. ### Analysing interactions

I have a 2x2x3 design, with two between-participants factors (goal specificity and interactivity) and one repeated-measures factor (difficulty). I...

• Replies: 0
• Views: 1,979
08-22-2010, 08:15 AM
54. ### Service Survey Statistically Significant Change

Hi All, I was really trying to find the answer from the thousands of similar posts here but had no luck... I have a customer service survey with...

• Replies: 0
• Views: 3,074
08-21-2010, 09:19 PM
55. ### Can't determine what test to use

I have this chemistry stat question. It has like a story to it, but the bottom line is, theres a guy who had broken glass in his coat, they...

• Replies: 5
• Views: 4,731
08-21-2010, 08:41 PM
56. ### K-S test interpretation in R

Dear all I am doing a Kolmogorov-Smirnov test in R in order to test if the two variables are from the same distribution. Turns out that I don't...

• Replies: 3
• Views: 46,383
08-21-2010, 07:27 AM
57. ### System Processing Forecast

I am working to come with a mathematical / statistical model for the following. We have a computer program that processes transaction with many...

• Replies: 0
• Views: 3,435
08-20-2010, 07:15 PM

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