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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: 196,763
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: 66,761
09-30-2005, 09:44 AM
1. ### Inter-Rater Reliability for Diagnostic and Continuous Measure

Hi All, I am hoping to compute the inter-rater reliability (IRR) of a diagnostic measure and a continuous screening measure. For the...

• Replies: 4
• Views: 1,177
04-19-2015, 12:45 AM
2. ### When study says 90% more likely (and it's merely an increase from 1% to 2% of people)

Study finds a person is 90 percent more likely to have explosive diarrhea when they eat a certain food (OR = 1.9; 95% CI, 1.3 – 2.8; p = .003). ...

• Replies: 0
• Views: 1,090
04-18-2015, 09:56 AM
3. ### Testing for moderated mediation

Hi everyone, I am using the Baron and Kenny approach to test for mediation. I would like to test for a moderation effect in path B. I know...

• Replies: 2
• Views: 1,312
04-18-2015, 09:56 AM
4. ### Choosing the correct statistical analyses

Hello, I have collected data using the Eysenck Personality Questionnaire (EPQ) that has 4 subscales and another self-created survey that measures...

• Replies: 0
• Views: 862
04-18-2015, 08:58 AM
5. ### Negative Confidence Interval

3. In two wards for elderly women in a nursing home the following levels of hemoglobin were found: Ward A: 12.2, 11.1, 14.0, 11.3, 10.8, 12.5,...

• Replies: 1
• Views: 1,376
04-17-2015, 07:57 AM
6. ### Controlling for earlier data points in a mediation (with covariates)

Hello :-) In my mediation analysis I have a personality trait as my X (independent variable), a behavior as M (mediator) and medical problems as Y...

• Replies: 0
• Views: 1,094
04-17-2015, 04:44 AM
7. ### Challenging Statistical Significant

In 18 patients with Everley's syndrome, the mean level of plasma phosphate was 1.7 mmol/l (millimoles per liter) with a standard deviation of 0.8...

• Replies: 0
• Views: 1,399
04-17-2015, 01:18 AM
8. ### Confidence Interval

In 22 patients with an unusual liver disease, the plasma alkaline phosphatase had a mean value of 39 IU/l (International Units per liter), standard...

• Replies: 0
• Views: 762
04-17-2015, 01:12 AM
9. ### Mean Significance Statistical Test

3. In two wards for elderly women in a nursing home the following levels of hemoglobin were found: Ward A: 12.2, 11.1, 14.0, 11.3, 10.8, 12.5,...

• Replies: 1
• Views: 1,548
04-16-2015, 06:41 PM
10. ### Research Question Statistical Method

In a study by Lapidus et al., one of the research questions was whether the proportion of physicians who screened patients in the emergency...

• Replies: 1
• Views: 1,360
04-16-2015, 06:40 PM
11. ### Two-sided test Hypothesis

2. In 18 patients with Everley's syndrome, the mean level of plasma phosphate was 1.7 mmol/l (millimoles per liter) with a standard deviation of 0.8...

• Replies: 1
• Views: 1,090
04-16-2015, 06:40 PM
12. ### Confidence Interval

In 22 patients with an unusual liver disease, the plasma alkaline phosphatase had a mean value of 39 IU/l (International Units per liter), standard...

• Replies: 1
• Views: 1,426
04-16-2015, 06:39 PM
13. ### Control variates, Monte Carlo integration

Exercise: Experiment with as many variance reduction techniques as you can think of to apply to the problem of evaluating P(N>2.5) where N~N(0,1). ...

• Replies: 0
• Views: 893
04-16-2015, 03:57 PM
14. ### Finding MLE by factor analyzing the correlation matrix

In the book "Applied Multivariate Statistical Analysis" written by Johnson and Wichern, they have mentioned that the MLEs ($\hat{L_z}$) are obtained...

• Replies: 0
• Views: 1,179
04-16-2015, 07:22 AM
15. ### Understanding the “computationally convenient uniqueness condition” of factor model

In the book "Applied Multivariate Statistical Analysis" written by Johnson and Wichern, they have mentioned about a computationally convenient...

• Replies: 0
• Views: 2,594
04-16-2015, 07:02 AM
16. ### trick for making samples with and without replacement

hi, is there any smart way to make samples with and without replacement for large populations for e.g if population is 1,3,5,8,9,7,5. waiting for...

• Replies: 4
• Views: 1,525
04-16-2015, 12:29 AM
17. ### a book which introduce neural network?

Dear all, I am currently working on model specification for neural networks and so look for a book which introduces neural networks including...

• Replies: 0
• Views: 938
04-15-2015, 10:23 PM
18. ### Strange post hoc analysis results?

Dear Talkstats I have made a dataset where i have treated the same cells with two different drugs. I have stimulated them with different...

• Replies: 0
• Views: 982
04-15-2015, 02:21 AM
19. ### Forecasting Rates of Return

Hi, I have 10 years of monthly rates of return between 31/03/2005 and 31/03/2015 on an investment which I would like to use to forecast the twelve...

• Replies: 0
• Views: 1,157
04-14-2015, 02:30 PM
20. ### Strange regression results

Hello, I'm working on analyzing data from a two-alternative forced-choice task, where participants had to choose between two options and were more...

• Replies: 0
• Views: 785
04-14-2015, 10:03 AM
21. ### Comparing means of datasets

Dear all, I am doing research with plants, where we compare different treatments and want to know if there is statistical difference between...

• Replies: 0
• Views: 843
04-14-2015, 03:27 AM
22. ### Help with normality test using SPss

hi all, I have an assignment question that ask to provide a summary statistic for a categorical data(male/female) with a total respondent of 100...

• Replies: 4
• Views: 2,535
04-13-2015, 01:54 PM
23. ### What statistical analysis to use for a ordinal scale questionnaire?

Dear Experts, Im a noob when it comes to statistics. So please pardon my lack of knowledge in this post. I need to do a statistical analysis on...

• Replies: 8
• Views: 2,246
04-13-2015, 01:15 PM
24. ### Unpaired t-test and F-test

Hello!!! I would like some help with t-tests. I perform unpaired t-test and the programm performs also F-test for equal variances. My t-test...

• Replies: 6
• Views: 2,511
04-13-2015, 07:06 AM
25. ### One-way ANOVA and planned comparisons - HELP!

Hi all, I'm currently running a Psychology experiment: the effect of background music on memory and mood. I will be using SPSS to conduct two...

• Replies: 5
• Views: 1,761
04-13-2015, 05:32 AM
26. ### What test to do to compare means, not fo experimental data, but of real world data

I want to also understand if the test to compare means are meant to be carried out only for experimental data. What about real world data? I...

• Replies: 8
• Views: 1,739
04-13-2015, 03:06 AM
27. ### Variance testing

Hello everyone, I would like a little help to statistics. I have to compare three groups. I am using GraphPad Prism Programm. I had applied...

• Replies: 4
• Views: 1,869
04-12-2015, 02:32 PM
28. ### When do I use chi square and when a t-test? I just don't get the difference...

Hi there, I'm trying to teach myself statistics from a book but I don't understand when I have to use t test and when chi squares. I tried to look...

• Replies: 5
• Views: 1,634
04-12-2015, 02:24 PM

Hi, I'm doing a study on shark movements via acoustic tracking. The data I get whenever a shark is detected is its ID, time (hh), depth (m, e.g....

• Replies: 1
• Views: 915
04-12-2015, 02:14 PM
30. ### homogeneity slopes

I'm doing some analysis of ANCOVA, but do not know if I'm not knowing interpret the results. I understand that an ANCOVA would be an ANOVA with the...

• Replies: 4
• Views: 1,906
04-12-2015, 11:37 AM
31. ### p Value + Sample Size in Chi Squared Tests

Hi All, This is my first post and I'm hoping someone could help me with the following question: a) The obtained p value for a contingency table...

• Replies: 1
• Views: 1,435
04-11-2015, 08:37 PM
32. ### ANOVA past exam question help

Hi everyone, I'm looking over last years exam paper and one of the questions asks me to interpret an one-way independent ANOVA SPSS output and report...

• Replies: 0
• Views: 866
04-11-2015, 06:01 PM
33. ### 0.00000 significance value

Hi everyone, New to Talk Stats, so be nice! I have looked for an answer to my problem on previous posts but have not been able to find anything...

• Replies: 4
• Views: 1,607
04-11-2015, 07:56 AM
34. ### normal distribution probabilities

The lifetime of a certain brand of battery is normally distributed with a mean value of 10 hr and a standard deviation of 0.8 hr when it is used in a...

• Replies: 1
• Views: 2,987
04-11-2015, 02:01 AM
35. ### hypothesis test

I have a sample of 250 credit card applications. 29 of them or 11.6% were processing errors. The goal is that no more than 10% of them are processed...

• Replies: 0
• Views: 1,168
04-10-2015, 06:52 PM
36. ### Is there a difference between z-score and effect size?

I just started teaching statistics to myself (I never had it in school but will need it when I start University). I have problems with z-scores...

• Replies: 2
• Views: 2,634
04-10-2015, 05:39 PM
37. ### Number of parameters in my model?

This is probably a very basic question, so my apologies! I'm trying to make sure I have the correct number of parameters in my model so I insert the...

• Replies: 3
• Views: 1,067
04-10-2015, 03:38 AM
38. ### is my regression incorrect ?

Hi eberybody I made a multiple regression and when I applied my estimated coefficients to the data to predict the dependent variable values the...

• Replies: 2
• Views: 1,408
04-09-2015, 03:34 PM
39. ### Wins > 50% for everyone in a pool of players

Is it possible for every single player in a pool of players to end up with a > 50% win/loss ratio. Providing that the game being played can have...

• Replies: 2
• Views: 1,356
04-08-2015, 06:27 PM
40. ### Long HW question..Struggling so much with this question

2. Let X1, X2, . . . , Xn be independently and identically distributed geometric random variables, as in Written Assignment 2 and the Midterm...

• Replies: 0
• Views: 1,209
04-08-2015, 03:01 PM
41. ### How to show that b1 and SSE are independent?

under normal sampling zero covariance implies independence. So I tried to solve COV(b1,SSE). COV(b1,SSE) = E =... =E(b1*SSE)-beta1*sigma^2*(n-2)...

• Replies: 0
• Views: 2,785
04-08-2015, 08:07 AM
42. ### Original source for skewness formulas

The past few days I've dug into Skewness and was trying to find some original sources. The most common formula for skewness in textbooks is:...

• Replies: 3
• Views: 2,330
04-08-2015, 07:42 AM
43. ### Normal Distribution Curve and Standard Deviation

Hi. I've been asked to implement a traffic light system in the office to highlight employees who are requesting to much or too little medical...

• Replies: 0
• Views: 1,293
04-07-2015, 04:34 PM
44. ### Statistical trend presentation of sports time results

Hi, I am an electronics engineer and I have designed a sports timing system for alpine skiing particularly for training. Results are sent to an...

• Replies: 0
• Views: 1,084
04-07-2015, 02:27 PM
45. ### Sample Size- number of additional participants required!

Hello! im currently running an experiment and my supervisor has asked me to calculate the number of additional participants i need to recruit in...

• Replies: 2
• Views: 1,336
04-07-2015, 09:17 AM
46. ### Simple Question

Hi, I'm learning basic linear regression and I have a question about model building. I was told that if a model contains higher-order terms...

• Replies: 3
• Views: 1,583
04-06-2015, 09:42 PM
47. ### Two girls one bonferroni - adjustment according to which families?

Hey guys We are two girls in need of some statistical guidance in our bachelor project in medicine. As it is the easter holidays, our advisor is not...

• Replies: 0
• Views: 988
04-03-2015, 07:50 PM
48. ### Help with which test to use? Basic question

I have a big data set containing students, and each student has a grade for 3 different subjects (writing, reading, and mathematics), and I need to...

• Replies: 2
• Views: 1,933
04-03-2015, 05:46 PM
49. ### Inference, estimator of moments

If X_1,..,X_n is a random sample with density f(x;\theta)=e^{-(x-\theta)}e^{-e^{(x-\theta)}} x \in\mathbb{R} and -\infty<\theta<\infty i) Find the...

• Replies: 1
• Views: 1,211
04-03-2015, 03:54 PM
50. ### Customer Segmentation

Hi all, Just wondering what approaches you can take when analysing customer data where you cannot determine whether a customer is active or...

• Replies: 1
• Views: 974
04-03-2015, 03:54 PM
51. ### Bayes estimator 2

If X ~ Poisson(\theta) and \pi(\theta)~exp(1)(prior). Find the Bayes estimator for P_\theta(X=0) with respect to quadratic loss I calculated the...

• Replies: 9
• Views: 1,846
04-03-2015, 09:42 AM
52. ### Choosing the right level of measurement

Hi, I have kind of a specific question relating to levels of measurement. First of all, my task is to choose the right measure of association for...

• Replies: 1
• Views: 1,233
04-03-2015, 09:25 AM
53. ### Projecting Future Values using historical

Hi all. I'm sure this has come up before - but, I was looking for a little help. I'm trying to put together a financial model that uses...

• Replies: 1
• Views: 3,045
04-02-2015, 08:53 PM

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