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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98 views
Frequency data differences test across two groups
I am looking into contrasting two groups with regards to frequency differences over a few time points.
To make it clearer:
I have for group 1, the frequency difference 5; 4; 1; 2; 3
and for group 2: ...
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1answer
91 views
Finding parameter $p$ of the Bernouilli distribution which is exactly 99% significant
I ran some experiments first. Afterwards, I looked for the parameter $p_{max}$ for which I can claim the chance a matrix has the ESP-property is $p_{max}$ or lower to a significance of exactly 99%. Is ...
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1answer
92 views
Dropping insignificant predictor in Poisson regression
I am doing a Poisson regression analysis and have found that the type of programme a student is enrolled on to does not have a significant effect on the outcome. When it comes to writing out the ...
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0answers
64 views
Constrained Least Squares: Variance-Covariance/Std. Error Estimation
I'm looking to obtain standard errors for constrained linear model estimation. I'd like to be able to estimate standard errors and confidence intervals for the coefficients of $\beta'$ estimated via:
...
4
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2answers
353 views
How to statistically compare two algorithms across three datasets in feature selection and classification?
Problem background: As part of my research, I have written two algorithms that can select a set of features from a data set (gene expression data from cancer patients). These features are then tested ...
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1answer
88 views
Determining the statistical significance of differences in a small dataset
What would be the best way of determining the statistical significance of the differences in concentration between trials of a dataset such as this one:
...
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0answers
29 views
Co-efficient of variation to eliminate frequency bias in vector
I need to determine the significance of a certain variable (i.e. cue) that co-occurs with an element of a particular class. I am working with vectors that are similar to this:
...
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0answers
50 views
Significance of Co-efficient of Variation
Is there a formula that is able to determine whether the difference between two co-efficients of variation is significant or if not is there a specific heuristic used to determine significance (i.e. ...
1
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1answer
76 views
Significance test for classification systems
I have several classification systems which I want to compare. The way I evaluate each one of them is using precision, recall and f-score. I want to compare the performance of every two of them using ...
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0answers
45 views
Analysis of infection data between two years using parametric or nonparametric tests?
I have three years of infection data from 6 different hospitals.
...
3
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0answers
61 views
Error Bars for Peaks in Noisy Data
I'm doing an experiment where peaks in amplitude $A$ (the dependent variable) are expected as one varies the frequency $f$ (the independent variable).
Based on our theoretical model,
Away from the ...
2
votes
1answer
60 views
How are user opinions compared?
Consider a situation where people are asked to rate a product on a scale of 1 to 5.
Product A has a rating of 3.95 based on 15,000 ratings. Product B has a rating of 4.2 based on 1000 ratings.
From ...
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55 views
significance test to use for multiple conversions in an A/B test
What is the proper way to measure significance in an A/B test, when a visitor can potentially "convert" more than once?
I understand a chi-square test or z-test are most often used for A/B testing, ...
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0answers
65 views
Test for significance for multiple non-normally distributed samples
I was wondering if anyone could point me in the right direction for what exactly I'm looking for.
I have binned multiple Boolean observations (1 or 0). The reason I made them Boolean is because it's ...
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1answer
78 views
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69 views
Can I calculate statistical significance for change scores using pre-post tests in a single subject study (n=1)?
I used two different scales as a measure of social validity. I can calculate the change, but can I calculate statistical significance? Isn't my N=1?
4
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1answer
136 views
Summarising significance tests for multiple independent variables
Having recently run an experiment, I have been left with a dataset that I don't quite know how best to handle, I think simply due to the number of independent variables to consider.
Setup
I have ...
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0answers
69 views
How to test significance for ranking and rating of multiple products among a single sample
Here are the specs -
-Single sample of n=200 respondents
-Each respondent evaluated 4 products
-Products were ranked 1st to 4th
-Each product was then rated on several attributes using a 9-point ...
0
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1answer
124 views
What are the important statistical methods? [closed]
For my Statistics class, I am building a module that can easily explain certain statistical methods to students, and get the required results. For this, I am developing a list of the most important ...
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2answers
91 views
What does statistical power mean when we are interested in the probability of correctly not rejecting the null hypothesis?
It seems that statisticians are usually only interested in statistical power. In other words, they are interested in the probability of correctly rejecting the null hypothesis.
What if we are ...
4
votes
2answers
255 views
Likelihood-ratio test or z-test?
Consider the following two logistic regression models:
$$
\begin{aligned}
&\text{Model A: }&P(Y=1)&=\frac{\text{exp}\left(b_1+b_2X_2\right)}{1+\text{exp}\left(b_1+b_2X_2\right)} \\
...
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0answers
277 views
How to find statistical significance between two years of data
I was asked to determine if the number of HAI infections in 2011 in statistically significant from the number of HAI infection in 2012. I performed a paired T-test using the actually numbers, but am ...
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1answer
53 views
Quantify significance between measured value and prediction (with error)?
I have a question about the proper way to describe the results I get to a prediction (both of which have statistical errors). I get a result with 1-sigma, let's say:
...
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1answer
111 views
Differences between groups
I am currently doing a research on effects of writing styles on the perception of reader.
Currently I have the following 4 groups
...
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0answers
81 views
Appropriate statistics for proportions where categories are composites of independent binary variables?
I have data in the form of three digit binary numbers (i.e. 100, 101, etc.) scored for each individual in my samples taken from two populations I wish to compare. The three numbers represent ...
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0answers
42 views
How to estimate the out crosses rate in crops?
How to estimate the out crosses rate in crops?
in have experiment included; main plot (1- seeds from open field 2- seeds from free pollinators cage 3-seeds from pollinator cage), sub plot (5 ...
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0answers
96 views
Formula for metrics shown in multivariate testing
In multivariate testing of full factorial combinations, how to calculate 'Chance to beat original' and 'Chance to beat all'.
This is shown in Google website optimizer tool.
I did some research and ...
2
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1answer
89 views
Regression - significance of a variable
I have been running a linear regression, and one of the variables was a discrete variable (3 categories), decoded into three binary variables.
I ran the regression in Stata. The first of those three ...
2
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3answers
147 views
Two fair coins, why increasing trials in prop.test not reduce false positive?
I am simulating two fair coins and running a prop.test, how come increasing number of trials doesn't decrease false positive? I'm suspecting it's in some underlying ...
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1answer
135 views
Achieving statistical significance in an A/B test
Out of one pool, I've randomly selected a small group (group A) and put everyone else in group B. Then, I'm observing whether or not they take a desired action.
If I'm looking to test at a 95% ...
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0answers
20 views
the approach for checking whether a process is stable?
I have two scenarios for time series data.
1) I have a uni-variate variable spanning across the time axis, are there any approaches or statistic to check whether this process is stable?
2) I have a ...
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0answers
116 views
Test for statistical differences between groups
What would be the best test to determine if differences among multiple groups are statistically significant? I'm doing a research of physiotherapist job satisfaction.
Here is a tabstat for ...
2
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0answers
83 views
How to test if two coins have different biases?
probably a noob question because I'm a noob.
I have two coins, A and B. For each coin I have a sample of the results I get by tossing it. My null hypothesis is that A has equal or higher probability ...
2
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0answers
69 views
How to test whether two means of categorisation generate significantly different results
If I have the following contingency table in which Novel.Cat is a new means of classifying some thing. Ref.Cat is the gold ...
2
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1answer
148 views
Include insignificant predictor with low variance?
In my regression, I have a predictor (measured in proportions) with very low variance (.002). It had no significant effect on the outcome due to a very high standard error of the regression ...
3
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2answers
149 views
Dummy's, significant and not significant
I have in my model two dummy's, for a categorical variable with 3 categories (native, EU-immigrant and non-EU-immigrant). The reference category is 'native'. These are merely control variables.
Now ...
6
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0answers
95 views
Estimating comparative success of different brochures
The Real World Problem
One of my clients is preparing to send a direct mailer to their subscribed user list, and this statistical challenge came up.
Their marketing team has 3 different brochures, ...
0
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0answers
59 views
Comparing strength of trend and seasonality for various levels of aggregation
I have a monthly time-series for which I've fitted the time-series regression model including linear trend and 11 dummy variables for seasonality. Then, I aggregated the original time-series to ...
0
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3answers
195 views
Direction of relationship in 2x2 contingency tables
I've been studying contingency table analysis and got to experiment a little bit with Fisher's exact test and Fisher's power test. Now I want to be able to determine the direction of the ...
4
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2answers
64 views
Testing significance of a data point against an data set
Background
I am currently testing conversions on a web page and would like to test if the changes I made yesterday produced a significant change in conversions.
The Data Set
For each day I test, I ...
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0answers
60 views
Determine if a statistically significant preference exists
I'm trying to determine if there is any statistically significant preference for objects (other content, products, etc) rendered in a module in a web page. I'm trying to create a simple experiment to ...
0
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1answer
162 views
Significance of Chi-square test for large sample
I am working on sample size of 70 . My observed and expected values are different
(Observed 586,
648,
526,
662,
658,
502,
..... so on for 70 samples and expected 570
634,
513,
647,
644,
490,
.....so ...
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0answers
57 views
A/B testing with multiple conversion goals
Suppose I run A/B testing with two variants on my website and track multiple conversion goals (e.g. goal a: post a comment, goal b: click facebook like button). To make it simple for now, a conversion ...
0
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0answers
159 views
Testing statistically significant difference between samples
I have 1 variable measured for 8 samples. so, for e.g. height of 8 men. I want to say something about: if height of men is significantly different amongst them. How can I do this?
Without any ...
0
votes
2answers
220 views
Testing statistical significance of male vs female enrolment preference percentages between two different fields of education
The problem I have is as follows. I have enrolment data describing the number of male and female preferences for two broad fields of education: i) Information Technology and ii) Engineering. The ...
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0answers
227 views
Statistical significance between two percentage change
I have two groups (test and control) and I wanted to determine the impact of a certain initiative on the test group. The comparison would be 4-month before the initiative and 4-month after. The ...
0
votes
1answer
61 views
Scientific way to show significance / test hypothesis
I am writing a report to show my results where, if there are more than 3 consecutive English character in a term, that term is noise. For example, "wooooh", "Noooo", etc. I have collected 100 sample ...
5
votes
2answers
362 views
Analysis of variance not statistically significant… but is there still a pattern to the data?
Problem I have a computer algorithm, and am attempting to measure the affect of a parameter (NS) on the output of the algorithm (SC). My hypothesis is that if the level of NS is lowered, there should ...
0
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2answers
98 views
Question on Survival Analysis
I'm working on a survival analysis project. In part of the project, I'm asked to "identify factors that may contribute to an increased risk of death". I have difficult time understanding what I'm ...
3
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3answers
102 views
Interpret statistically significant betas with poorly performing models
I am using logit models to predict whether or not children are unhealthy (binary indictor). Many of my models have statistically significant relationships between predictors of interest (ie, if the ...
