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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: 197,168
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: 66,955
09-30-2005, 09:44 AM
1. ### Statistical analysis between group after within group analysis?

Hi guys, I have 3 groups and each group has its own pre-test and post-test. What I need to do is : after I compare pre-test and post test in each...

• Replies: 4
• Views: 8,526
08-06-2010, 06:15 AM

The Voyage of the St. Andrew Throughout the picturesque valleys of mid-eighteenth-century Germany echoed the song of the Neul&#228;nder (newlander)....

• Replies: 0
• Views: 8,524
04-27-2008, 12:16 PM
3. ### Estimating sample size for reliability study

Hello, I'm having problems calculating the required sample size for my PhD study. I have designed my first study, which is comparing moral...

• Replies: 1
• Views: 8,520
06-15-2013, 02:11 PM
4. ### I really need help with this matched pairs experiment!

Do consumers prefer the taste of a cheeseburger from McDonald's or from Wendy's in a blind test in which neither burger is identified? Describe...

• Replies: 1
• Views: 8,518
11-15-2006, 03:20 PM
5. ### finding observance significance level

Help i have a stats final and im not quite sure what to do to solve this problem: It has been estimated that the 1991 G-car obtains a mean of 35...

• Replies: 2
• Views: 8,512
04-21-2009, 09:25 PM
6. ### Box's test in MANOVA

Hi, I have run MANOVA with 3 groups in the independent variables and 8 variables for the dependent variables. I have 4, 5, 5 subjects in each group...

• Replies: 3
• Views: 8,488
07-09-2013, 02:23 PM
7. ### two way ancova problem

I have to analyze a set of data, and while I know roughly what I'm doing, I am having some problems making conclusions. I will outline the data and...

• Replies: 7
• Views: 8,472
09-28-2009, 02:39 PM
8. ### when to use the median and when the mean ?

Good morning, I have an assignment, I need to specify with examples, in which situation the mean is the best central measure and in which the...

• Replies: 21
• Views: 8,469
01-08-2012, 01:25 PM

Hi I am doing a two way anova assignment and need to do the fmax for the six treatment groups. For the fmax statistic, you need the df for each 6...

• Replies: 1
• Views: 8,466
02-10-2009, 04:24 PM
10. ### Mardia's Multivariate Normality test interpretation

Hello I obtained the macros for doing Mardia's Multivariate Normality test in spss from this website: http://www.columbia.edu/~ld208/ the...

• Replies: 0
• Views: 8,462
10-22-2010, 10:29 AM
11. ### 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: 8,460
08-30-2010, 10:37 PM
12. ### Regression through the origin?

Hi guys I am wondering what does "Regression through the origin" means in the real world practice? I've been researching on it and found out...

• Replies: 6
• Views: 8,460
01-09-2011, 06:55 AM
13. ### combining frequency and agreement likert scales

Hi I have a four item construct in a survey I am working on. 3 of the items are measured using a frequency likert scale (never, rarely,...

• Replies: 0
• Views: 8,459
12-21-2008, 11:00 PM
14. ### Interaction effects one way ANOVA

HI, Just wiondering, is it possible to have interaction efefct in one way ANOVA? I think it is a bit not logic but I need confirmation. Thanks!...

• Replies: 3
• Views: 8,455
02-19-2012, 09:07 AM
15. ### Help - questions re: Empirical Rule/Chebyshev

Hello: Does anyone know how to approach these problems? Any help would be greatly appreciated. The mean IQ of 200 patients in a psychiatric...

• Replies: 5
• Views: 8,454
05-08-2006, 08:34 AM
16. ### Unbiased estimator

Consider the uniform distribution on . Find an unbiased estimator for \theta based on the geometric mean of a sample of size n: ...

• Replies: 2
• Views: 8,430
03-10-2010, 10:13 AM
17. ### Sampling Procedure Help Needed for Constructing a Confidence Interval

Hi all. Quick background: I am a 64 year old lady going back to college to get my Bachelor's. I haven't taken a college course in 30 years :shakehead...

• Replies: 8
• Views: 8,429
07-26-2013, 12:49 PM
18. ### repeated-measures t statistic

What values can be estimated using the repeated-measures t statistic? a) the value of an unknown population mean b) the difference between two...

• Replies: 1
• Views: 8,424
11-27-2006, 03:22 PM
19. ### Help with this one, please?

Suppose certain coins have weights that are normally distributed with a mean of 5.358 g and a standard deviation of0.052 g. A vending machine is...

• Replies: 3
• Views: 8,420
11-21-2008, 01:03 AM
20. ### Phi and Cramer's V

There must be something I'm not getting with these measures of association for nominal variables. Please help me understand. What I've got so far...

• Replies: 4
• Views: 8,418
11-03-2011, 02:27 PM
21. ### This is probably easy for you but very hard for me!

Can someone please help me figure out how to do this problem? A professor knows that from past experience that the time for students to complete a...

• Replies: 6
• Views: 8,413
02-22-2014, 02:10 PM
22. ### Help: STATISTICS- HYPOTHESIS TESTING PAPER

Question: JUST an INTRO paragraph on THE SUCCESS RATES IN ONLINE STUDENTS....it is for the following paper, but I only need an INTRO PARAGRAPH ...

• Replies: 1
• Views: 8,410
07-18-2010, 06:41 PM
23. ### T-scores, n1, n2, and probability

Maybe this should have gone in the probability section, but I'm not sure... soo... here ya go. I hope someone can help, I have an exam tomorrow. ...

• Replies: 0
• Views: 8,407
04-18-2011, 12:26 AM
24. ### What is the difference between an odds ratio and a risk ratio?

Hi - struggling to understand what the difference is between an odds ratio and a risk ratio? :confused: Can anyone help? Thanks!

• Replies: 2
• Views: 8,395
10-11-2011, 03:45 PM
25. ### Derive Expected Value of Yhat

Yhat = 1/n Derive E(Yhat) and show that Var(Yhat) = ((1.25σ^2)/n) I don't know how to work with the constants to get the Expected Value and...

• Replies: 17
• Views: 8,392
BGM
11-06-2011, 05:50 AM
26. ### t-test on geometric means?

I have 2 groups of dilutions (titres) that I would like to compare. The thing is, the mean for titres is usually the geometric one so I feel that I...

• Replies: 1
• Views: 8,386
BGM
07-13-2011, 01:30 PM

Find the probability that in 200 tosses of a fair six-sided die,a five will be obtained at most 40 times. A)0.8810 B)0.1190 C)0.0853 D)o.9131 ...

• Replies: 2
• Views: 8,385
04-14-2008, 12:47 PM
28. ### When/ when not to use Z scores to compare data

In comparing 2 groups of numbers, could you give me any examples of when would it be (1) beneficial (2) when it would not be beneficial to first...

• Replies: 4
• Views: 8,384
12-12-2010, 06:10 PM
29. ### Use of Tukey-Kramer

In the context of one-way ANOVA, when should the Tukey Kramer procedure not be used?

• Replies: 1
• Views: 8,380
07-25-2008, 12:12 AM
30. ### One Way ANOVA with grouping using Tukey method.

Hello! I have conducted One way ANOVA using Tukey method in minitab. I am now interpreting the grouping results. I am a bit confused. If the...

• Replies: 2
• Views: 8,372
04-18-2012, 01:13 PM

I have two Poisson distributions with different means. I want to combine them. Can I assume that the resulting distribution is also a Poisson? ...

• Replies: 3
• Views: 8,371
03-26-2008, 05:28 PM
32. ### Application of T-Distribution

Hello Guys, Ok. I have never came across a situation like this before so I am not quite sure if I could use T-Distribution to construct a...

• Replies: 2
• Views: 8,371
06-28-2010, 02:12 AM
33. ### Joint CDF's and pdf problem

I am trying to solve part of a question whicg goes as: Q: Suppose X and Y are two continuous random variables whose joint density function is ...

• Replies: 7
• Views: 8,369
09-02-2006, 12:18 PM
34. ### Census vs. Sample

I am looking for more clarification on how a census survey is usually analyzed and reported. While there is a lot of information on how to go about...

• Replies: 7
• Views: 8,369
05-07-2012, 04:03 AM
35. ### Percentile Help

I am lost on this one. Please help. Find the percentile for the data point Data Set: 4, 13, 10, 6, 4, 4, 13, 6, 4, 13, 2, 13, 15, 5, 9, 4, 12,...

• Replies: 4
• Views: 8,358
01-16-2008, 09:35 PM
36. ### Interpretation of a Q-Q plot and Shapiro-Wilk test

I have the following output from a shapiro-wilk test: Shapiro-Wilk normality test data: goalTime W = 0.9486, p-value = 0.05751 And the Q-Q plot...

• Replies: 3
• Views: 8,357
12-09-2012, 10:06 AM
37. ### Help with statistics homework?

1). If the hypothesis test is conducted using α = .025, this means that: a. there is a 2.5% chance that the null hypothesis is true b. there is a...

• Replies: 1
• Views: 8,355
05-30-2010, 02:43 AM
38. ### Minimum number of replicates required to calculate the standard error of the mean

Hi, I know how to calculate the standard error of the mean, and was happily doing so with some of my data when a colleague said it was not...

• Replies: 0
• Views: 8,348
03-14-2009, 07:50 PM
39. ### Skewness "rules of thumb"

I'd like to get an expert evaluation of these two statements: 1. If the mean of a distribution is greater than both the mode and the median, you...

• Replies: 2
• Views: 8,345
10-20-2010, 08:55 AM
40. ### Testing if median of a sample equals zero

Hello, I would like to ask you for your opinion the following problem. (My knowledge of statistics is more or less basic.) There is a sample with...

• Replies: 2
• Views: 8,343
Keo
05-13-2008, 02:29 PM
41. ### New Here- Need some help with chebyshev's theorem

The average number of pages in a mystery book is 220 with a standard deviation of 20. Using Chebyshev's Theorem, what is the range of values in which...

• Replies: 1
• Views: 8,339
02-21-2008, 08:44 AM
42. ### Minimum sample size log normal distribution

I am working with a group here and have a relatively simple question. We know the p90 and p10 of our distributions and usually think the...

• Replies: 4
• Views: 8,339
08-17-2010, 10:09 AM
43. ### sample mean z-score

If a sample is selected from a normal population, then the probability that the sample mean will have a z-score less than z=2.55 is.......?

• Replies: 1
• Views: 8,333
11-13-2006, 12:35 AM
44. ### Why does the determinant always equal zero for a matrix of consecutive numbers?

Hi. Why does the determinant always equal zero for a matrix of consecutive numbers? This applies whether the consecutive numbers are in the matrix...

• Replies: 2
• Views: 8,321
07-31-2011, 07:29 PM
45. ### Multivariate Regression - I think!

Hi, I'm performing a psychological study about gender differences in attraction. Participants select between a number of figures that vary in...

• Replies: 22
• Views: 8,306
03-03-2006, 12:28 PM
46. ### Mixed models: Calculating ICC for model with a random intercept and a random slope

Hello All, I have a question about how to calculate an intraclass correlation coefficient in a mixed model that has both a random intercept and a...

• Replies: 8
• Views: 8,295
08-14-2017, 06:26 PM
47. ### Mahalanobis vs. cook's distance

Hi, I just ran a linear regression analyses with 4 variables (baseline variables predicting wave 4 drop out). When looking at the casewise...

• Replies: 0
• Views: 8,277
02-09-2009, 10:58 AM
48. ### How to E= 0 and Var = 1 in a standardized normal distribution?

I wanna prove that expectation and variance of a standard normal distribution are 0 and 1, respectively. It seems there is no way to do it...

• Replies: 4
• Views: 8,271
09-17-2008, 08:52 PM
49. ### $60 - tutor wanted$60 an hour. R code Logistic and Poisson Regression Central Limit Theorem ANOVA Single, two pop tests Simple and Multiple Linear Regression...

• Replies: 36
• Views: 8,267
12-03-2011, 01:44 PM
50. ### Critical z value problem

Need help with this problem Assume that the data has a normal distribution and the number of observations is greater than fifty. Find the...

• Replies: 2
• Views: 8,260
02-15-2009, 10:35 AM
51. ### Random Walk on a Circle - Show distribution of X_TN is uniform? Help please!

Hello, I am trying to solve the following problem: Consider the simple random walk on the circle {0,1,...,N-1} started at 0. Show the...

• Replies: 2
• Views: 8,255
09-28-2011, 04:29 PM

Hi there, I'm attempting to do dimension reduction/data reduction with PCA. The goal is to extract "factor" scores to use as independent variables...

• Replies: 2
• Views: 8,236
07-01-2010, 01:55 PM
53. ### 3-way interaction: calculation of the SEb

Hello, Im working on the statistics of my thesis and I am afraid Im stuck. I conducted a regression analysis with three-way interaction and now I...

• Replies: 4
• Views: 8,229
08-10-2009, 01:22 AM

The centers for disease control say that about 30% of highschool students smoke tobacco (down from a high of 38% in 1997). Suppose you randomly...

• Replies: 2
• Views: 8,227
02-17-2008, 11:59 PM
55. ### Sample Overlap - what is the effect on stat tests?

A survey was done. 1000 respondents. 250 were younger males. 250 were younger females. 250 were older males. 250 older were females. I want to...

• Replies: 3
• Views: 8,222
09-16-2011, 06:11 AM
56. ### Showing that its an unbiased estimator..

Hey guys....bit stuck on something - i'm having trouble showing that the difference of two population means ie. (y2-y1) (with hats on top) is an...

• Replies: 2
• Views: 8,221
10-14-2010, 09:00 PM

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