Statistical significance refers to the probability that, if, in the population from which this sample were drawn the true effect were 0 (or some hypothesized value) a test statistic as extreme or more extreme than the one gotten in the sample could have occurred.

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19 views

Interpretation of the coefficient of dummy regression?

I found this for a week, but I still cannot find anything about it. In a regression, Y = a + b * X + controls +e If we add dummy D=1 for group A and 0 for others, it becomes Y = a + b*X + c*D + ...
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8 views

How to find weber fractions from a confusion matrix

I have a confusion matrix for a 4 class classification problem which looks this: My hypothesis is that group 3 is easiest to classify. Somebody suggested me that I can find weber fractions from this ...
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1answer
37 views

identify different points

I have a large scatterplot, with about 100,000 (x,y) points. The x coordinate is the set of numbers from (1 to ~100,000) - in other words, no 2 points have the same x-coordinate. The y is mostly ...
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7 views

Comparing two Usability questionnaires

i'm seeking for advice and confirmation for data analysis for my master in computer science. briefly, i had develop a software and now testing it using usability questionnaire for improvements. i had ...
4
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1answer
162 views

Test that two normal distributions have same standard deviation

I have two normal distributions, and I want to test whether they have the same standard deviation, I really don't care about the mean. My idea is: de-mean both of them and then use Kolmogorov-Smirnov ...
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1answer
13 views

variable reduction

I have a set of features and a score in my dataset. Score is defined based on these features. What technique is used to see which of the features is more effective in the total score? I used anova and ...
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0answers
3 views

Finding correlation of attributes based on known decisions

If there are two matrix of data, rows are all a person (under 50 users). In the first dataset, columns are attributes (over 500 columns) of a user with the rating 0 for does not exist, 1 for exist. ...
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27 views

Which Test to Use?

I was wondering if someone could help me regarding the statistical tests I should use. Basically I have the following: 1) I carried out a survey asking teachers and students to rank components in my ...
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41 views

Birthday “Paradox” — with a different perspective

Background: Many people are familiar with the so-called Birthday "Paradox" that, in a room of 23 people, there is a better than 50/50 chance that two of them will share the same birthday. In its more ...
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1answer
22 views

How can I statistically formulate football player attributes similar to Football Manager games or footballdatabase.eu?

I have collected player match history statistics like runs, shoots, passes and such. I would like to come up similar attribute values (psychical, mental, technical) to Football Manager game or ...
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0answers
10 views

Statistical test needed for a pre-experimental study [on hold]

Hi I am doing a pre experimental study with one group. what all statistics I need to do for the confirmation of the results? i need to know the inferential statistics which has to be done for this ...
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2answers
22 views

Overall Significance vs. Individual Variable Significance in Mutliple Regression

I'm running a statistical analysis for work in which I'm trying to determine which (if any) key economic indicators influence our sales. Here is the summary data that I'm getting when I run a ...
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18 views

Test similar to Kruskal-Wallis test but for multidimensional vector

I need to do the similar kind of test as Kruskal-Wallis test, but for a multidimensional vector. Would you please kindly suggest such kind of test or provide some references for N-dimensional case
2
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2answers
59 views

Kruskal–Wallis Test not significant but Mann Whitney U significant

I have a non-normalized dependent variable and an independent variable broken down into 4 groups. As such, I used the Kruskal–Wallis analysis to look for significant differences in the ranks of the ...
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0answers
20 views

inference Single sample [closed]

Can someone Answer this question. Thanks in advance. 6.17 the one with black circle. Right now i have no idea how to approach and solve it.Any help would be highly appreciated. Thanks.
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30 views

Statistical Significance or Unambiguous Direction of Influence?

With this post I want to put forward an interpretation of the concept of "Statistical Significance" in the context of "frequentist" Hypothesis testing that rings very convincing to my ears. I am not ...
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0answers
11 views

Significant variables, but no improvement on predictive ability of model

When running binary logistic regression in SPSS, I obtain first a measure of the predictive ability of a model without independent variables (base model). This is then compared with that of the model ...
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0answers
9 views

Pre/Post analysis without control

Quite a newbie to this, any info or pointers are appreciated, but please be as precise as possible. If I have a feature in general that was launched mainly to improve the user experience, but ...
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1answer
56 views

Great model prediction, but no significant variables

I am performing a binary logistic regression. I have developed a simple model which I am testing using the SPSS application. This first determines the predictive ability of a baseline model without ...
1
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1answer
21 views

Statistical significance in binomial variable: how many tests needed?

I have a problem that occurs randomly, in approximately 2 % of tests. I am testing fixes, to prevent the error from occurring. The error occurring once would mean it is still happening and would ...
2
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1answer
64 views

Optimal Allocation

A campus population of size N=9000 is to be surveyed by a stratified sample for the prevalence of a certain disease based upon three strata of respective sizes $N_h$ = 1000, 3000, and 5000 for h = 1, ...
2
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0answers
119 views

Question about Dynkin Lehmann Scheffe Theorem

I'm self-studying for an examination, and I would like to understand how to use the Dynkin Lehmann Scheffe theorem for an applied question. I am using Bickel and Doksum's "Mathematical Statistics" ...
2
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3answers
28 views

Does the order of magnitude of sample values influence p-values and effect size?

When using an independent-samples t-test to compare two variables, do the absolute values of the samples affect the test statistic and the effect size? In other words, is it easier to obtain ...
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0answers
5 views

Testing dispersion of values between condition on a group

I may have a tricky question. I have a within design where every participant is tested in 2 conditions. I want to compare the dispersion of the measure, for the two condition, with the hypotheses that ...
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0answers
4 views

Two Data Collection Method Groups

I have collected around 20 respondents by post; and by email around 150 respondents. I would like to know whether I can combine the two groups, the independent sample t test shows that there is a ...
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1answer
18 views

Cronbach's Alpha low- significant results

One of my variables has a low Cronbach's Alpha. I continued to run an planned contrast to test my hypothesis and the results were significant. I understand that the results should be interpreted ...
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1answer
18 views

Finding If A Replacement Manufacturing Test System Fails More Units

I'm currently writing software that replaces an existing legacy system, which tests units against different engineering specifications. Since I'm currently verifying everything works, and I was able ...
1
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1answer
23 views

Reducing the number of interaction terms in a diff-in-diff model?

Is there a way to reduce the number of interaction terms in a diff-in-diff model to make the results easier to interpret/present? Background: I'm trying to run the following diff-in-diff regression: ...
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1answer
26 views

Confidence Interval and Signifcance test Question

I have done the first part of the question already I just need help on the second part. You read in a U.S Census Bureau that a 99% confidence interval for the mean income in 2005 of American ...
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0answers
11 views

How to treat “Missing Value Analysis” test results (problems)

I have a problem with Missing Value Analysis. I am using SPSS version 20. I am trying to test whether missing values are at complete random. As I know in order to ensure missing values are completely ...
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0answers
18 views

R - power.prop.test, prop.test, and unequal sample sizes in A/B tests

Say I want to know what sample size I need for an experiment in which I'm seeking to determine whether or not the difference in two proportions of success is statistically significant. Here is my ...
3
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1answer
24 views

Significant difference between proportions, found at sample size below that suggested by power analysis

I'm looking at data from experiments that have been run to look for a difference between proportions, 1-tailed. In many of these it has been found that there is a significant difference between the ...
2
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0answers
36 views

Are significance tests only about sampling error or other forms of variation also?

When we study differences between a treatment and control group in an experimental setting, we want to test whether those differences are big enough that we can conclude they are not simply due to ...
2
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2answers
174 views

Comparing performances during a race between 2 groups, which test should I use?

Imagine I organized a race between 2 types of ants. Type A and B. At the end of the race, I have the ranking, which looks something like : ...
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2answers
241 views

Interpreting one- and two-tailed tests

How do you report results that give you a p-value of 0.08 for a two-tailed test and a p-value of 0.04 for a one-tailed test? Generalizing the issue, if you obtain a p-value between 0.05 and 0.9999 ...
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61 views

F-statistic value is too high for my model

Number of obs = 501 , Method: Fixed-effects regression Number of groups = 101 F( 10, 100) = 3422.31 , Prob > F = 0.0000 , ...
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20 views
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1answer
31 views

R - Analyzing Relationship Between Two (or more) Binary Variables

Say I have two vectors: Action.Taken = c(0,1,0,0,1,1,0,1,0) Success = c(0,0,0,1,0,1,0,1,0) The first tells me whether or not a specific action was taken in a ...
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1answer
23 views

Many groups with a single large element and a lot of small ones - How to assess?

I have a sample of 100 groups, each with 50 elements. All elements in each group are characterized with a single "size" value. The sizes of all the elements in a group (with 50 elements) are ...
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2answers
140 views

Why is it wrong to refer to results as being “highly significant”?

Why do statisticians discourage us from referring to results as "highly significant" when the $p$-value is well below the conventional $\alpha$-level of $0.05$? Is it really wrong to trust a result ...
2
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1answer
42 views

correct statistical test to compare 2 poisson distributions

I know there are similar posts, and I've read a few of them already, but none of them give explanations that I actually understand. I'm completely new to statistics and am finding it more difficult ...
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0answers
33 views

What is a correct way to test these data for significance?

I have data on 1548 disease cases and 1137 controls. Specifically, for each person, I have a certain score $n$. I am interested in the following: First, for either group, I want to know if the ...
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1answer
24 views
2
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3answers
27 views

Kolmogorov-Smirnov of two heart rate samples

I'm accumulating a lot of vital signs from emergency department patients, and would like to assess if different features yield significantly different distributions. Eg. for heart rate I have 888.424 ...
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2answers
139 views

Is multiple logistic regression the right choice or should I use univariate logistic regression?

I have a set of data (~ 90 cases) and an outcome of a diagnostic test. I have collected factors that were determined before the test that could predict the outcome of the test. Now some of the data ...
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0answers
26 views

Combining several a/b tests

Imagine I have two ads (banners), A and B. They can be placed at several different positions on the page (only one banner is shown on the page). Each position can be viewed as a separate a/b test. I ...
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1answer
21 views

Confidence Interval Application to a time series

So I'm not sure if I 100% grasp confidence intervals. Say I have a huge data set of a bond prices from 1996 to present in MINUTES. Suppose I separate each data by day. If I were to use a Dickey Fuller ...
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1answer
46 views

FDR (multiple testing correction) with skewed p-value distribution

I am confused with multiple comparisons adjustments. I have a $p$-values with lot of ones ( due to many scores in foreground are 0) from a fisher-exact test. I get some $p$-values which are ...
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1answer
56 views

Doing post-hoc after a not significant interaction in mixed ANOVA

I conducted a mixed design ANOVA with two within-subjects factors: FactorA (2 levels), FactorB (2 levels), and one between-subjects factor: Group (2 levels). My main hypothesis regards the interaction ...
3
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2answers
190 views

Is p-value also the false discovery rate?

In http://surveyanalysis.org/wiki/Multiple_Comparisons_(Post_Hoc_Testing) It states "For example, if we have a p-value of 0.05 and we conclude it is significant the probability of a false discovery ...