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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: 196,982
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: 66,868
09-30-2005, 09:44 AM
1. ### Standard deviation and sample size

Hi. I have no background on statistics, so please just go down to fundamental for me. But here are some basic questions about statistics and standard...

• Replies: 12
• Views: 4,114
12-16-2014, 05:52 AM
2. ### Plugins to write in statistiscal notation in Wordpress sites

Hello, What plugins do you recommend to write statistical notation in Wordpress sites ? Thank you

• Replies: 0
• Views: 1,515
12-15-2014, 06:21 PM
3. ### Which inferential test?

Hello, The hereunder is an exercise I have to complete. I am having issues with answering questions. Study: Researchers were interested in...

• Replies: 4
• Views: 3,184
12-15-2014, 02:19 PM
4. ### Trying to strenghten validity of sample

Hi, this is my second post in this forum (the first one in the new member thread). I am turning to this thread in hope for getting some advice on...

• Replies: 4
• Views: 1,931
12-15-2014, 04:42 AM
5. ### degrees of freedom in ANCOVA?

So we were given this problem: Parasites are energetically expensive and can have both sub-lethal and lethal effects on snails (the hosts). To test...

• Replies: 0
• Views: 4,029
12-14-2014, 02:54 PM
6. ### How to calculate sample size manually ?

Hello If My Confidence Level = 95% Margin of error = 5% Number of observation = 211 How can i calculate the sample size ? Can someone...

• Replies: 2
• Views: 2,565
12-14-2014, 11:40 AM
7. ### Which analysis to take

Hello I strugle with the question which analysis I have to take. I ve got 2 categorical ordered data eg. frequencies of bad moods: never, 1 to 3...

• Replies: 1
• Views: 1,332
12-14-2014, 04:13 AM
8. ### The z-scores of the 68-95-99.7 rule aren't matching up with the values in my z-table

The z-scores from the 68-95-99.7 rule, which are 1, 1.96 (or 2), and 3 according to my textbook, arent matching up with the values i get if i try to...

• Replies: 2
• Views: 7,156
12-13-2014, 11:39 PM
9. ### Nested Case Control Study

Hi, I have 195 cases and I want to find 4 randomly controls. Can I use propensity score matching to find controls matched to the cases? ...

• Replies: 0
• Views: 1,195
12-13-2014, 06:46 AM
10. ### Research Help!

Hi all. What is the appropriate statistical test for comparing two seperate groups who's data is independent from one another? Different people in...

• Replies: 3
• Views: 1,563
12-12-2014, 05:31 PM
11. ### Regular or paired t-test?

I need to compare results of running an air dispersion software at different scenarios (varying in the amount of the dispersed material) for 6...

• Replies: 3
• Views: 1,400
12-12-2014, 02:43 PM
12. ### Wilcoxon and Mann-Whitney Test

Hello, I need to do one of these two statistical tests, I have a database on the consumption of fuel rods in each of the regions of my country,...

• Replies: 14
• Views: 2,216
12-12-2014, 01:21 PM
13. ### Expected Value of Y = max (X1, X2, X3, .... , Xn)

I'm having a hard time figuring out what the expected value of Y = max(X1, X2, X3, ... , Xn) with pdf (x;θ) = 2x/θ^2. So it is the nth value of order...

• Replies: 1
• Views: 5,499
BGM
12-11-2014, 11:34 PM
14. ### Comparing Groups 2 sample T-test or Anova

So I have a word problem that I can't get my head around. Perhaps because the wording of the question is leading me down the wrong path about the...

• Replies: 3
• Views: 1,794
12-11-2014, 03:21 PM
15. ### Databases

I have been asked to develop a universal data base to house all of our company's wildlife survey data that is currently housed in Excel files. We...

• Replies: 2
• Views: 891
12-11-2014, 11:46 AM
16. ### How to calculate? Gretagarbo?

Hi, I'm a doctor and conducting a huge study for Pfizer. Now all the data is collected and i'm trying to make statistical calculations. Total...

• Replies: 1
• Views: 1,246
12-11-2014, 09:01 AM
17. ### Standard deviation of two sets from only individual set descriptive statistics

I have two sets of numbers and I have access to their averages and standard deviations. However, I do not have easy access to the actual numbers...

• Replies: 2
• Views: 1,308
12-11-2014, 08:22 AM
18. ### What type of curve is this?

The left one is a logistic curve / sigmoid function e.g. y=1 / 1+exp(-bx) What would be the typical name for the curve on the right / typical...

• Replies: 1
• Views: 941
BGM
12-11-2014, 03:29 AM
19. ### Confidence interval conceptual question

Why is creating a confidence interval not a viable alternative to a chi-square or an ANOVA? I'm guessing it's because a CI can't give more...

• Replies: 0
• Views: 1,257
12-11-2014, 12:01 AM
20. ### How to compare if two sets data are the same

I'm trying to compare measurements that I took to measurements that someone else took on the same exact things. Im trying to see if they are...

• Replies: 4
• Views: 1,528
12-10-2014, 07:51 PM
21. ### Do statisticians often work with scientific experiments?

I don't know anything about statistics(or life or anything)... anyway, I am interested in knowing how statistics ties into the scientific method. ...

• Replies: 0
• Views: 968
12-10-2014, 02:58 PM
22. ### Required sample size to distinguish means of two binomially distributed rv

Hello, Currently trying to work out the best way to calculate the number of samples that would be required to get a certain confidence interval. ...

• Replies: 0
• Views: 785
12-10-2014, 01:18 PM
23. ### What is the best descriptive stats to present this data

I have a table where the major categories are on the columns and they total to 100% for each column. Then the subcategories are on the rows and each...

• Replies: 2
• Views: 2,408
12-10-2014, 05:41 AM
24. ### help w/ anova test selection & factors (groups)

Hello there. Stats noob here I'm an IT major so apparently stays is required for me. I have an assignment here and one of the questions is really...

• Replies: 0
• Views: 1,210
12-10-2014, 03:13 AM
25. ### Pass Rate Calculation for Multi-tiered Tests

Hello, I am working on a project in an educational setting that requires individuals to complete multiple tests. In particular, an individual must...

• Replies: 0
• Views: 2,111
12-09-2014, 07:30 PM
26. ### Can Z, t, and chi square critical values be either positive or negative?

As the question states. I thought it might be possible for a z and t because of the two tails in a normal distribution. Not sure about chi because...

• Replies: 2
• Views: 2,720
12-09-2014, 07:17 PM
27. ### Choosing alpha for Pearson's correlations

Does anyone know of any good references that discuss how to choose alpha for a Pearson's correlation?

• Replies: 10
• Views: 1,838
12-09-2014, 04:48 PM
28. ### Multiple imputation on categorical (dummy coded) data

Hello, I have a question regarding multiple imputation for categorical variables, and hope very much that someone can answer me. I am using SPSS...

• Replies: 0
• Views: 2,119
12-09-2014, 09:56 AM
29. ### Some confuse about Regression Model(with example)

I am a college student who has studied basic statistics. Recently, i have read a paper which call "Creating a Profitable Betting Strategy for...

• Replies: 0
• Views: 1,191
12-09-2014, 05:40 AM
30. ### Stepwise regression model with dependent variable categorical (help)

Hello , Can I use the step wise regression model with a categorical dependent variable? Is coding the dependent variable as 0 or 1 is enough to...

• Replies: 7
• Views: 1,469
12-08-2014, 05:54 PM
31. ### Least square line of best fit

I am looking for a references for the least square line of best fit. Preferably a journal paper. Thanks!

• Replies: 3
• Views: 1,421
12-08-2014, 04:41 PM
32. ### Strugling with Ttests

Hi everyone, This is my first post on this forum. I'm on a Sports science course and during a practical we had each participant measure their...

• Replies: 5
• Views: 1,579
12-08-2014, 06:37 AM
33. ### importing data in spss

i have my stress questionnaire with the side heading of 6 each side heading containing 10 questions totally 60 questions are there. how should i...

• Replies: 2
• Views: 1,376
12-08-2014, 05:17 AM
34. ### What is the difference between factor and cluster analysis

Can you please explain me the difference between those 2- cluster and factor analysis. And if you can please give me a simple example to reinforce...

• Replies: 1
• Views: 2,456
12-08-2014, 02:59 AM
35. ### Forecasting the future gallup poll results - what methods should be used?

Hello guys, My first post in TalkStats. Lately I have been interested in politics. It has been few years since my statistics studies and therefore...

• Replies: 0
• Views: 1,118
12-07-2014, 07:20 PM
36. ### Right closed or left closed histograms

What difference does it make if histograms are right closed (left open) or left closed (right open). Please, someone do help me?

• Replies: 9
• Views: 2,452
12-07-2014, 05:34 PM
37. ### How to start this problem? Factor analysis?

I am not sure what statistical test to use here. Should I start form factor analysis? Data on concentrations of 13 different chemicals in wine...

• Replies: 2
• Views: 1,489
12-07-2014, 10:44 AM
38. ### Question on Mean, SD and SEM

A professor has a sample of 500 subjects. The mean is 40, median is 20, range 10-100. a. Could this professor calculate a useful interval with...

• Replies: 1
• Views: 2,171
12-07-2014, 01:48 AM

I need to hypothetically propose the best statistical analysis for the following problem? Any ideas? If you do, can you please give rationale. Thank...

• Replies: 3
• Views: 2,144
12-06-2014, 08:20 PM
40. ### Cox model: covariates and likelihood function

Hi everyone, I study maths but I am dealing with the cox regression model, given by the equation h(t)=h_0(t) exp{b_1X_1+...+b_nX_n} but I could not...

• Replies: 0
• Views: 1,175
viv
12-06-2014, 10:36 AM
41. ### how to adjust economic value for financial crisis?

Hi all On the beginning, I would like to say that I'm newbie in econometrics. However, I've been asked for preparing Chow test to check if there...

• Replies: 0
• Views: 1,038
12-06-2014, 08:57 AM
42. ### Intro Stats - 3 Part Question

Hi, I'm first year stats and have just found your forum. I am not sure about the wording of this question. I'm wondering if it is throwing me off...

• Replies: 4
• Views: 1,344
12-05-2014, 07:55 AM
43. ### how to calculate effect size for 4 people :)

Hi, Let's say I have group X (treatment) and O (control). In group X: person A: pretest :15 postest: 20 person B: pretest: 14-postest:18 ...

• Replies: 0
• Views: 1,206
12-05-2014, 02:48 AM
44. ### Is it true that factor values are the eigenvalues of the factors?

I wonder whether it is Is it true that factor values are the eigenvalues of the factors? I tried to find what factor value is but I can't find it....

• Replies: 2
• Views: 1,098
12-05-2014, 02:38 AM
45. ### Help with standard deviation calculations, please?

Hello, I am taking an online statistics class and having trouble with this chapter's homework. The following question has nine parts. I have...

• Replies: 0
• Views: 2,581
12-04-2014, 10:18 PM
46. ### What statistical calculation to use and which R function?

Here's the data I have... I have a "national" sample (the control) showing the actual number and percentage of people in the sample that have a...

• Replies: 1
• Views: 1,669
12-04-2014, 04:07 PM
47. ### Question on power analysis/interpretation when sample size is lower than recommended

A friend of mine in med school asked if I could comment on a study his team ran since I have a little bit of a background in statistics, but to be...

• Replies: 2
• Views: 1,628
12-04-2014, 11:09 AM
48. ### Find if additional value is significantly different among a group

I'm trying to determine if an additional number's difference among the mean is statistically significant. Let's say for example, I have: SET_A = ...

• Replies: 2
• Views: 1,051
12-03-2014, 03:19 PM
49. ### How often one distribution is larger than another

Say you have two distributions: DISTRIBUTION 1: Average: 200 Standard Deviation: 40 DISTRIBUTION 2: Average: 190 Standard Deviation: 37

• Replies: 4
• Views: 2,096
BGM
12-03-2014, 02:31 PM
50. ### Which test: dichotomous and ordinal variables

I'm really starting to get peeved with different interpretations of which statistical test to use. I have two variables that I'll illustrate ...

• Replies: 6
• Views: 2,588
12-03-2014, 10:26 AM
51. ### Using sample proportion to construct standard error?

Hi All, In my stats book, we are told that to construct the standard error of your sample proportion (p(1-p)/n)^.5, you can just replace p with...

• Replies: 0
• Views: 978
12-03-2014, 08:17 AM
52. ### Stats help Urgent!!

Hello, I have an assignment due tomorrow and i can't seem to figure out this question. Question 1: Carlinville, Illinois, has just started an...

• Replies: 10
• Views: 2,804
12-02-2014, 11:53 PM
53. ### Number of sample mean for normal distribtiion & matrix in linear regression

1. By Central Limit Theorem (CLT) , the sample mean will have an approximately normal distribution (even though the population is not normally...

• Replies: 3
• Views: 1,895
BGM
12-02-2014, 11:28 PM

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