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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Does the birth date of professional boxers matter? Prove/disprove what an astrologer might predict

As a followup to my question about the birth month of boxers, I am posing the fundamental question along with my hypothesis (testing if there is any truth to a conclusion an astrologer might make): ...
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21 views

Regression without intercept [duplicate]

I saw that here explain how to get the formula for getting a regression without intercept but I already know it (for example in R you get it outomatic with ...
5
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2answers
121 views

Statistical significance of birth month of professional boxers

I looked at the birth dates of the top 100 ranked professional boxers of all time (67 of them to be exact). 40% of them were born during certain 3 month-long time periods. If birth date of boxers ...
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19 views

How to determine significance of polynomial?

I'm running a model where both a 2nd or 3rd order polynomial would seem to fit the data. I'm trying to decide which one to use. In the quadratic model (panel fixed effects) the first and second order ...
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1answer
22 views

Using sample standard deviation to estimate the standard error

In single-sample hypothesis testing, we can collect a sample and test whether the mean of this sample might have been drawn from the same population as some hypothesised mean. We use the standard ...
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2answers
33 views

How to correct for absolute values when looking at relative values?

Apologies if this is a duplicate. I have a website with a large number of URLs, and I also have data on the number of unique page-views and online feedback generated for each URL. I would like to find ...
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18 views

Different means with non-significant anova

I did an ANOVA test summary(aov(m$Y~m$type)) and I get a p-value of 0.067 i.e. the means are equal. But my means by type are these ...
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1answer
143 views

Statistical significance test for multiple binary classification problems

Let $C_1$, $C_2$ be two binary classifiers, which are used to classify some data (images, videos, etc) to $30$ different classes, using an one-against-all approach. Then, we have two $30$-dimensional ...
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19 views

Confidence Interval of Calculating Precision

The problem I'm trying to solve has the following setting: Let $X_1, \dots, X_N$ be a data set where each $X_i \sim Categorical(p_{TP}, p_{FP}, p_{TN}, p_{FN})$ s.t. $\sum\limits_{k \in ...
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39 views

How many points you need for significance difference

I have a data set where 300 people tested 6 out of 7 products Column A- the respondent ID. Each respondent makes up 6 rows Column B- Product codes. Each of the 6 rows for each respondent has 1 out ...
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1answer
26 views

Denominator term in Chi-Square-Test for association in a contingency table

The general formula for the Chi Square Test for association in a contingency table with $I$ rows and $J$ columns, and cell counts $n_{ij}$ is $$ \chi^2 = \sum_{i=1}^I \sum_{j=1}^J \frac{(n_{ij} - ...
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12 views

significance difference test for a cell in 2x2 confusion matrix

I have 2 confusion matrix that looks like the following. Columns indicate predictions, row indicates actual values. ...
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29 views

How can MANOVA report a significant difference when none of the univariate ANOVAs reaches significance?

I would just like to ask if it is normal for the values from my multivariate tests to be significant but for the values from my univariate tests of between-subjects effects table to be insignificant. ...
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1answer
40 views

Appropriate statistical analysis to use

I have built and tested a computer application, which involved two participant groups (Group-A with existing knowledge of databases and Group-B without knowledge of databases). I was required to apply ...
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14 views

Test to compare against a known value

I had a set of values of 40 observations, and I want to test their significance different with a known actual value. What test should I carry out in finding out the significance difference?
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1answer
32 views

How do I know when my results here are statistically significant for user ratings?

I have a survey where I ask people their ratings for something. If they vote 0-4, I rank them as "con", 5-7 as "on the fence," and 8-10 as "pro." So now I want to split up all my data by region, such ...
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1answer
13 views

Is it valid to run unpaired t-tests with large N in one condition and small N in the other?

Basically, I have collected sets of data from two demographic groups. One of my demographic groups (say, Male) I have lots and lots of data (N=182). In my other demographic group (say, Female) I have ...
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17 views

Determining statistical significance in difference between two CRF models

I have trained two Conditional Random Field (CRF) models Ma and Mb in CRF++, the first using a simple set of features, the ...
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1answer
11 views

Comparing effects of different methods when each method has multiple levels

I'm working in retail and we are trying to determine the effect (on units sold) of reducing an expense for a set of products within a product group. We have two methods of reaching this goal. One is ...
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1answer
27 views

What statistical analysis should I use for Likert-Scale data? [duplicate]

I am trying determine if there is a significant difference in preference of activities between males and females.I'm using a survey with the following question on 7-point likert scale: Question 1: I ...
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2answers
63 views

How to determine whether a variable is significant using Pr (>Chi) and Df?

I wonder how can I determine whether a variable is significant using Pr (>Chi) and Df? Take following ANOVA table as an example, I know variable type is ...
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29 views

the Chi-squared distribution and Mahalanobis

I'm doing some simulations in C++ and OpenGL (2D and 3D) for navigating a robot in unknown environment known as SLAM. I'm using Extended Kalman filter as an optimal estimator. In SLAM problem, once ...
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38 views

T-test statistical significance [duplicate]

I'm running a regression on does degree type affect income. I am not 100% sure if my t-statistics are significant or not? Can you guys help me out? Which coefficients are or not significant and at ...
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11 views

Trend Survey Statistical Tests

I am designing a trend survey using a Likert style survey. I have three opinion questions, each with the same choice of responses ranging from Not Likely to Very Likely. Are there any statistical ...
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6 views

What type of within-subjects design should I use? Error-rates, Distances

I know I need to use a within-subjects design for this, but I can't figure out what type of design to use. I am an amateur at statistics and haven't taken a statistics course in years. I will try to ...
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1answer
23 views

Significance of changes in mean values over time

I have 5 mean life satisfaction values for 5 different years; I have to find out if there is a significant relationship between the survey year and life satisfaction. How should I proceed? I was ...
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1answer
34 views

Is this a right way to use paired t-test

Problem Description I want to enhance a photo and I have 3 software to do that, out of which 2 are my own. I show users 2 photos and ask them to choose a better one. Now, I compare software 1 vs. 2, ...
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1answer
73 views

How many individuals must be measured to determine the true mean?

I saw this was asked earlier, but I also have the same question. This was the question: "Anatomy: The human height is the distance from head to toe. When populations share a genetic background and ...
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16 views

Statistical significance test for student performance variation among classes

I'm trying to find out if differences in the variation of student performance among different classes are statistically significant. I got the values by grouping each student into their class, then ...
2
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1answer
16 views

Can I justify using a one-tailed test in for this interaction effect?

I have an experimental setup with 2 factors, site and disturbance treatment. I have reason to suspect that plots at site A will be more affected by treatment than plots at site B. My response ...
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2answers
40 views

How to find if a difference is statistically significant?

I have a web crawler that scrapes items on an hourly basis and expect to get 375 items every time. In the past 10 runs, I have scraped the following number of items: [360, 361, 363, 364, 368, 372, ...
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5answers
110 views

Understanding standard errors on a regression table

I'm beginning to look at tables more and more in my studies, but I don't understand the significance of the standard errors below the coefficient estimates. I know if you divide the estimate by the ...
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0answers
14 views

How to change the color and width of lines with par function [migrated]

I have a question about the par function in R. I want to change the color and/or width of a line in a graph with par function. (I am using par function because the gaps.plot command below does not ...
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54 views

Which test to use to check the difference between samples of percentages?

I have data measured from 14 samples between two conditions. I want to check difference between them. But the data is normalised and is in terms percentage (0-100). For example ...
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1answer
32 views

High reliability imply difference?

Suppose a test has scores between $0$ and $50$. Alice scores a $34$ and Bob scores a $42$. Does a high Cronbach's $\alpha$ imply that the Alice and Bob's scores are statistically significantly ...
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2answers
42 views

Influence of correlation in linear regression

I have an output $Y$ and some input values $X_1, \dots X_p$, where the number of variables are smaller than the number of observations ($p<<n$). I want to understand which of the variables have ...
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2answers
171 views

How to interpret standardized regression coefficients and p-values in multiple regression?

I've been using R to analyze my data (as shown in example below) and lm.beta from the QuantPsyc package to get the standardized ...
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18 views

How to measure whether the number of points belonging to a cluster is statistically significant

I have a set of data in five clusters (say C1 through C5). From this, I also have the probability of a random point belonging to each of these clusters (p1% through p5%). I select a subset of my ...
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6 views

Creating a normalized histogram of log intensities with GEO datasets [migrated]

I'm trying to create a density/log intensity histogram of a normalized GEO microarray dataset. I have tried doing this several different ways, but unfortunately I have had little to no luck. What is ...
3
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1answer
51 views

sample size too large? [duplicate]

I always thought larger sample sizes were better. Then I read something somewhere about how when sample sizes are larger, it's easier to find significant p-values when they're not really there (i.e., ...
0
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1answer
35 views

Pearson Correlation has quizzy results

I investigated experiments with SPSS and following values were out. I have a question that in which case is possible to get Feature 1 in Group A+B as significant p<.05 while either Group A and B ...
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1answer
15 views

Benjamini-Hochberg and GEO2R

I'm currently using GEO2R to analyze a microarray data set. There is an option to generate the 250 most statistically significant genes, which calculates an adjusted p-value using the ...
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1answer
42 views

Which stats tests to use? Bee flight activity quantified during an eclipse

I'm trying to perform a statistical analysis but not sure what test is most appropriate. The experiment and snippet of sample data are below: Methods: Bee flights from a beehive were recorded, ...
5
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1answer
140 views

Unrealistically high significance when marginalizing over large number of parameters

The setup I've tried to reduce the problem to a self-contained subset for this question, but it still ended up being pretty long. Sorry about that! I have a set of observations of a set of objects ...
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1answer
24 views

Frequency significantly different from zero

I've got a few frequencies, and I'm trying to work out if each of the frequencies is significantly different from zero. Most of the frequencies I can eyeball, but I wanted to have some for of ...
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14 views

Statistical significance test for confusion matrix

I have a doubt regarding, which statistical significance test to apply on a confusion matrix. Say for example there is a two class classification problem. The confusion matrix is given as follows: ...
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0answers
21 views

Sample an Interval on Continuous Variables, Intervals, Statistical Significance, Sampling - Applied Stats Question

Let's say I have a segment of pipe of length $X$ that I want to test the integrity of by way of a hydrostatic pressure test. That is, I isolate the ends of the pipe and pump water into it until it a ...
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3answers
50 views
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37 views

Testing for statistical differences of quantile regression line slopes

If I were to compare the statistical similarity between the slopes of OLS regression lines from two independent samples, I would use a t-test to test if the slopes are equal or not. I'd like to ...
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1answer
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Can the endogenous variable be insignificant while the instrument is significant?

I suspect that this is entirely possible since the endogenous variable coefficient can biased in many possible way, thus leading to a near 0 estimate despite having a real causal relationship. More ...