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# Forum: Statistics

Statistics course and homework discussion. Elementary statistics.

1. ### 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: 66,620
09-30-2005, 09:44 AM
2. ### 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: 196,561
07-16-2014, 11:01 AM
1. ### History & Development of Statistics....

Hi, I have been given the task to write on the Topic: History & Development of Statistics. This task was given to me by my HOD(Head of Department...

• Replies: 10
• Views: 2,125
07-11-2013, 09:16 AM
2. ### Maximization problem!

Hello, I have a dataset of 5-dimensional vector X={x_i: i=1,2,3,4,5} and their corresponding y where y is a real-valued number. How can I derive...

• Replies: 6
• Views: 2,131
05-24-2012, 10:32 AM
3. ### kurtosis skewness and Jarque Bera interpretation

I am getting a value of 27.202 of kurtosis, Jarque bera of 861.4684 with probability 0.000000 and skewness of 5.078,,,,,,,,,, what to interpret are...

• Replies: 2
• Views: 8,780
12-06-2011, 08:58 AM
4. ### non-central chi-square distribution

Dear All I do not have enough background in statistics. Can any one please tell me how to finde probabality for noncentrally chi-sqaure random...

• Replies: 3
• Views: 8,029
11-15-2007, 09:34 AM
5. ### independence of observations and 'best' observation

Hello forum. This is my first post. I'm pleased to find somewhere I can ask questions about, and hopefully, help others figure out how to do good...

• Replies: 1
• Views: 3,086
06-07-2009, 06:35 PM
6. ### Statistics

I have some homework for my stats class. It's fairly simple, but I just can't seem to figure out which test is appropriate for the situation. Can...

• Replies: 3
• Views: 2,650
07-07-2010, 03:49 PM
7. ### How to compare changes in different groups

I have two separate datasets, each with two independent (unpaired) measurements. So there are four measurements in total. Within each dataset, I...

• Replies: 2
• Views: 1,774
07-30-2012, 04:05 PM
8. ### Likelihood Ratio test

I have a pdf where I would like to test for the following hypothesis: H0: θ1=θ1,0; Ha: θ1>θ1,0, and f(x) =(1/θ1) exp((-x-θ2)/θ1), if x>θ2, and 0...

• Replies: 8
• Views: 1,855
04-27-2014, 10:51 AM
9. ### T-Test: Accounting for country level & difference of two time points

Hey everyone, another student and I are currently working on a paper in which we face a problem that we just cannot solve. Probably it is super easy...

• Replies: 0
• Views: 1,795
02-25-2016, 11:08 AM
10. ### Directed acyclic graph

Hello I'm a beginner at epidemiology and have an assignment where I'm trying to create a DAG using dagitty to determine what to adjust for when...

• Replies: 1
• Views: 1,046
05-11-2015, 04:27 PM
11. ### Distribution, data aggregation/simplification

Hello, I'm working with fisheries data and I have the quantity in kg of each species caught by boat, by day. There is one species that is dominant...

• Replies: 0
• Views: 2,284
12-05-2008, 07:40 AM
12. ### Likert scale help

Hi guys, I'd really appreciate any help, I'm useless with statistics and I'm very confused! Basically, I have gathered data using a 5-point Likert...

• Replies: 0
• Views: 2,153
01-22-2010, 09:01 AM
13. ### Need a stats test for Temperature test.

Hello, I have an average temperature value for a day in January (-14) and I want to see if it is different then the average value for the entire...

• Replies: 1
• Views: 1,614
03-22-2013, 06:46 AM
14. ### Standard Deviation

Ok...so i need to find the values above and below the mean using standard deviation. I have the mean and the standard deiviation, but the mean...

• Replies: 2
• Views: 1,999
09-09-2008, 12:32 PM
15. ### least squares predictions

I need to figure out what percent will reduce the prediction error of a least squares equation with a set of data....My prof said to use the r^2...

• Replies: 1
• Views: 2,163
10-09-2008, 10:31 PM
16. ### Urgent indicator semivariogram problem

Hello. I'm trying to create an spatial indicator semivariogram (variables transformed to 0 and 1), but i got the same graph for both. i'm using...

• Replies: 0
• Views: 3,710
05-29-2011, 01:08 AM
17. ### The appropriate regression analysis

The study is about the factors (Independent Variables) affecting a choice between two alternatives (Dependent Variable). The study includes a...

• Replies: 6
• Views: 2,086
10-27-2016, 07:22 PM
18. ### From variance to 95% confidence interval: Is this done right?

Hello I have a forest inventory project where I am trying to estimate the total forest wood volume (in cubic feet) with a 95% confidence...

• Replies: 4
• Views: 439
09-13-2017, 05:39 PM
19. ### Test whether the SD of multiple normal distributions differs between two genes

Hi, I am comparing data on gene expression between two different genes that have been tagged with GFP. Gene expression is measured using flow...

• Replies: 0
• Views: 1,145
12-14-2012, 03:13 PM
20. ### Question on conditional expectation

Hello, I would like to know, whether the following is true: E = f(x,y) Unfortunately I was unable to find an answer on the internet...

• Replies: 0
• Views: 1,050
02-06-2014, 04:55 AM
21. ### Sign of covariance

Hello everyone, I would like to know, if the following relationship holds in general: \left. \begin{aligned} cov(X,Y)& < 0 \\ % use \quad...

• Replies: 1
• Views: 1,301
05-08-2014, 11:27 AM
22. ### 2x2 Anova, im struggling to report the assumptions

Hello, I've ran a 2x2 anova and am trying to report the assumptions but would like to make sure ive done it correct, statistics is my weak point!...

• Replies: 3
• Views: 830
02-22-2016, 04:45 PM
23. ### Regression Equation question

Can you tell me, if you have a regression equation with two partial regression coefficients (slopes), can you guestimate the p-values for each...

• Replies: 1
• Views: 2,630
12-15-2006, 06:33 PM
24. ### Inventory Control

I have this question on Inventory Stock and I need a solution to it. Guys, I need help. charls. Question: Mr Steve is a merchant which deals on...

• Replies: 0
• Views: 2,238
07-24-2008, 04:03 AM
25. ### predicting discrete variable (age) from continuous data and transformations

Hi, i have data on age (years) and a continuous variable (weight for example). I want o predict the age using a linear regression. However, i...

• Replies: 4
• Views: 3,986
01-25-2012, 03:48 PM
26. ### help with contour plots

I am producing contour plots with curvature, basically like hills that look like asymetric lobes when looked at from the top. I was wondering if...

• Replies: 0
• Views: 1,765
01-21-2008, 04:40 PM
27. ### Normal Distributions

ok, I have this one problem that I cannot figure out for the life of me. It's probably really simple, but I really just can't figure it out. Any...

• Replies: 0
• Views: 2,822
04-03-2006, 11:35 PM
28. ### Unequal (small) sample size?

Hello I am very new to Statistics and I would much appreciate if someone could help me answering this question. I have carried out a survey which...

• Replies: 0
• Views: 4,284
04-18-2011, 07:37 AM
29. ### Making Seasonal Data form Monthly

I've got a climate data set spanning a number of years in monthly intervals, but I'm only interested in what happens in winter months - October...

• Replies: 0
• Views: 1,018
03-24-2013, 12:30 PM
30. ### How to compare a change in proportion over time across two groups?

I have two groups of subjects, A & B, which differ in terms of whether they have pulmonary disease or not ("A" have pulmonary disease, "B" do not) ...

• Replies: 0
• Views: 6,675
06-21-2009, 04:07 AM
31. ### Which standard deviation to use?

Hi, I'm new here on the forum. I'm from the Netherlands and working in the field of acoustics. I have a question, which might be quite simple....

• Replies: 1
• Views: 2,043
11-15-2007, 09:25 AM
32. ### How do I find standard deviation without a sample size ?

I have been working on a problem with the help of a friend who is pretty knowledgeable on the subject. I don't think this is possible to find a...

• Replies: 2
• Views: 4,114
02-21-2015, 10:44 AM
33. ### Effect Size and Significance

Can effect size be used to predict significance or vice versa? I was asked what size effect would be needed to reach significance? Can this be done?...

• Replies: 1
• Views: 2,421
08-15-2007, 11:00 AM
34. ### Is Chi Square Even The Right Test?!?

I recently collected data for a study that mesaured participants comprehension ratings of collision avoidance warnings. Each warning was presented...

• Replies: 0
• Views: 2,617
09-22-2007, 01:43 PM
35. ### Interaction terms in survival analysis - equivalent to glm contrasts?

I am wondering if there is a way to interpret an interaction term from the coefficients rather than just looking at the survival curves? The...

• Replies: 0
• Views: 1,631
02-21-2014, 02:10 PM
36. ### Sample size

Hello i am hoping someone can help me with this question below Will my sample size increase, stay same or decrese, if i go from comparing...

• Replies: 1
• Views: 1,254
07-12-2012, 03:31 PM
37. ### Hypothesis Testing question

Hi, I am new to this forum. I need desperate help. I am taking a QMB 3200 class and there is no book so I am lost. Here is my question: ...

• Replies: 6
• Views: 3,242
12-14-2005, 12:50 PM
38. ### Hypothesis testing

Here I am again....Thank you so much for helping me out yesterday. I am lost when it comes to Hypothesis testing....What do you think about this...

• Replies: 4
• Views: 4,176
12-14-2005, 02:52 PM
39. ### Asymmetric (skewed) Data and Mean

Hello, I have a bunch of sample data of the form: -0.90,.-0.89,-0.35,-0.55, .... +9.96 ie. 9 out of 10 data points are small negatives and the...

• Replies: 1
• Views: 3,778
07-12-2007, 11:56 AM
40. ### Standardizing Similar Groups with Different Internal Variables

I am on the student government at a college, i feel like there has to be a way to create a scoring system for a organization. For example like lets...

• Replies: 0
• Views: 1,594
10-25-2011, 10:25 PM
41. ### t test confusion

Hi first post, thanks for your help. Background: I've designed an interface for remotely controlling unmanned vehicles. The interface will be...

• Replies: 1
• Views: 1,916
03-20-2008, 08:08 PM
42. ### equation for critical values of q

Hello, I am looking for the equation(s) in how to calculate critical values of q. As you know q is used in doing Turkey's multiple comparison. I...

• Replies: 1
• Views: 8,014
10-24-2010, 07:52 PM
43. ### 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: 1,318
09-19-2012, 08:11 PM
44. ### Factor Analysis/Prinicpal Component Analysis: Reporting to APA Style

Hello All, Desperate for help! I've performed a principal component analysis on a pilot study of a questionnaire I created. I have removed poor...

• Replies: 1
• Views: 30,411
02-12-2008, 03:16 PM
45. ### How to calculate sample size

I learned it before and i know it's basic but need your help, i want to calculate the sample size needed (alpha - 0.05 , power -0.8) in the following...

• Replies: 2
• Views: 6,281
04-13-2010, 07:20 PM
46. ### Help with Medical Stats

Okay, I am a doctor in the UK, and have conducted a survey of practice before and after a teaching course. Stats was never my strong point! I now...

• Replies: 0
• Views: 2,711
12-08-2008, 06:04 AM
47. ### Shewhart Control Chart Calculate Alpha Errors Under Rules

Two decision rules are given here. Assume they apply to a normally distributed quality characteristic and the sample size is n=5. Rule 1: The...

• Replies: 0
• Views: 5,729
02-06-2012, 08:29 PM
48. ### Evaluating differences between repeated measurements of one group to another

I'm having difficulties understanding what type of statistical testing I need for my questions. My measurements include the following: Organism 1 ...

• Replies: 0
• Views: 1,005
05-31-2014, 05:16 PM
49. ### One sample t-test

Hi, This is probably an embarrassingly easy problem but I've looked all over the place and I can't seem to find the answer, or at least I don't...

• Replies: 10
• Views: 2,033
05-21-2012, 04:28 PM
50. ### confidence interval test

Hey everyone- I am rather new to statistics and am having difficulty with the following question: For a group of 10 individuals who have been...

• Replies: 0
• Views: 2,700
10-22-2007, 09:27 AM
51. ### class width

would the class width be: 1. 20-40 this class width would be 20 2. 11.5 - 14.3 this class width would be 2.8 rounded up to 3 is this...

• Replies: 0
• Views: 4,775
10-22-2007, 10:36 AM
52. ### t test or CI

a group of 10 students subjected to stress display a mean number of 120 heartbeats/min with a SD of 4. If you wanted to be 95% confident that...

• Replies: 0
• Views: 2,217
10-22-2007, 06:52 PM
53. ### Chi-square analysis -- evaluating the difference between two groups

I am assessing a study on the habitat distribution of the woodland vole, where the independent variable is habitat type and the dependent variable is...

• Replies: 3
• Views: 4,794
03-22-2009, 05:13 PM
54. ### help with count regression for rate data using SAS

Hi, I am a beginner SAS user and studying CDA with baby steps. I am using Agresti's book, "An introd to CDA" 2nd ed, which I like very much. ...

• Replies: 1
• Views: 2,628
03-04-2012, 01:12 PM
55. ### Measurement accuracy

This should be a fairly simple question. If I take say, 200 temperature readings, recorded to the nearest degree, with half (ie 100) having "less...

• Replies: 0
• Views: 2,007
03-03-2009, 11:33 PM
56. ### Global Temperature Measurement Accuracy

Weather station temperature data is currently measured by automatic weather stations to an accuracy of 0.1 degrees but recorded to the nearest...

• Replies: 0
• Views: 2,827
03-04-2009, 03:16 PM

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