Tagged Questions

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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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
24 views
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4 views

Statistical significance for occurrence of words in text classification?

I am looking for a statistical significance to test to assess the occurrence of words in text classification for the different classes. Assume we count the number of occurrences of words per class and ...
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18 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
35 views

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 ...
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0answers
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Central nodes in a set of networks with shared nodes

I have a set of weighted networks, each represented as a complete graph composed of nodes and connections with weights (see also "weighted networks" on Wikipedia). All networks share the same nodes ...
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22 views

regarding skip the intercept term once it is not statistically significant [duplicate]

After building the regression model, the intercept value is not statistically significant Is that reasonable to just skip it in the final regression model?
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1answer
20 views

Performing significant difference tests in endline evaluation

we have conducted an endline survey and now comparing the result with baseline survey. I am interested to find significant difference between baseline and endline. One of sample questions is given ...
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0answers
5 views

post-hoc testing in clustering analysis 1 feature

I've read that a post-hoc testing of the results of a clustering analysis is incorrect to perform. If I understood well this is true if the data are multidimensional and the purpose is to find out ...
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1answer
35 views

What statistical analysis should I use for my study?

In my psych class we were testing to see if groups of men or groups of women would be more helpful in an emergency situation (we are testing for the bystander effect), and we are testing to see if ...
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0answers
26 views

How to statistically validate a threshold?

I have a set of 3 parameters that were measured for several individual (each dot of the dotplot is one individual). I am trying to define subpopulations of individuals based on these measurements. ...
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0answers
14 views

Regressions and statistical significance [duplicate]

Why does the statistical significance of the variables in a multiple regression lower compared to individual simple regressions?
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1answer
40 views
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1answer
42 views

linear regression

I am reading a paper and come across the following information: ...
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20 views

the reason that adding one more predictor variables will cause lm model to be all NA

I have a data set with multiple predictor variable candidates, and try to experiment with different combinations. During the experiment process, I tried using the first 9 variables, ...
2
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2answers
42 views

Why do we compare p-value to significance level in hypothesis testing of mean?

I know that: p-value = P(observed or more extreme outcome of sample mean | Null hypothesis is true) But why do we compare it with significance level (alpha) while determining if it is high or low? ...
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1answer
22 views

Earliest significance in A/B test

I'm working on a problem/assignment where I'm given some activity logs from a website where an experiment was conducted. I'm asked to determine the earliest time when a statistically significant ...
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0answers
11 views

When is appropriate to combine two treatment groups from one study into a composite whole for a meta-analysis?

The treatment groups I would like to combine appear to be virtually the same, at least by generic label for each group, e.g., groups with the same treatment but implemented at different sites or ...
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0answers
18 views

Statistical test for Comparing 6 classifiers over 5 datasets

I did the Friedman test to compare 6 classifiers which are tested over 5 datasets. The null hypothesis was rejected so I proceed with the post-hoc Bonferroni. The X classifier is always first on all ...
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1answer
30 views

How to calculate sample size for this study design?

I am trying to find out whether the number of participants I recruited (N=42) so far is sufficient for my study in which: there are two interfaces (say A and B). ALL students in the study will try the ...
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0answers
33 views

Effect of binary variables on binary outcomes

All I have two sets of data. One where people bought and another where they did not. For each sample in the two sets, I have ~3000 binary independent variables. Each dataset has about 1000 samples. ...
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0answers
20 views

Hypothesis testing on groups of time series data

I have some experimental data from two groups, where each group contains data from $n$ subjects. The data are in the form of a time series for each subject, but are not all the same length. To be ...
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0answers
13 views

How to determine significance across categories of binary data?

I have subjects that fit into one of three, mutually exclusive groups, "favorable," "intermediate," and "unfavorable" based on their genetics. They can then be classified as either a "responder" or a ...
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0answers
19 views

Can I use K-S test to distinguish distributions?

I am using the kolmogorov smirnov test to differentiate between distributions. My example is below where I am comparing DATA2 and DATA3 to DATA1. From the image, I was hoping to quantify that DATA1 ...
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0answers
7 views

Need Insight on Measuring Variable Effect

I apoligize in advance for the wall of text. I'm working on a project in which I have been asked to determine what factors influence employees leaving our company. Also, it would be useful to be able ...
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1answer
41 views

Exact two sample proportions binomial test in R (and some strange p-values)

I am trying to solve the following question: Player A won 17 out of 25 games while player B won 8 out of 20 - is there a significant difference between both ratios? The thing to do in R that ...
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0answers
35 views

calculate statistical value of the mean of a mean of a mean

EDITED FOR CLARITY Hello, Considering the picture below each values X could be identified by the indeces X_g_s_d_h ...
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0answers
10 views

Nested Anova for same group of participants

I am dealing with the following problem. I want to compare how some geometric measurements from the same participants can be connected with the existence of a disease. So the nested anova should like ...
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0answers
3 views

Gibbs sampling scheme on Ozone35 data set [migrated]

I'm attempting to run a Gibbs sampling scheme on the data set Ozone35 from the BayesVarSel package in R. Here is the info on the data set Ozone35: ...
2
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1answer
68 views

Wrong Intepretation of Kruskal Wallis Test in R

I have some data (called egecNonmated) in R and I am trying to show that the distributions of a variable (MatchScore) are identical across three different Categories (Cat). I am using a box plot to ...
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1answer
45 views

How to prove the siginicance difference level in this data?

I have collected a set of data of 52 weeks of actual output and demand. Actual 1100 1300 1400 1500 1600 1100 1200 1600 2100 1300 1600 1300 1600 2200 2300 1700 1800 800 1400 900 2100 1400 1800 1900 ...
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1answer
25 views

Bootstrap significance test

I'm using the bootstrap method to test my experiment results for significance. I have two sets (say A & B) of 50 grades, for which I want to test whether their means are significantly different. ...
0
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0answers
26 views

Median confidence interval

It is asked to prove that if $X_1,...,X_n$ is a random sample from $X \sim U(\theta -1/2, \theta +1/2)$, then $$P( \theta \in [X_{(1)}, X_{(n)}])=1-2(\frac{1}{2})^n$$ Note that $\theta$ is the ...
0
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1answer
20 views

How to find three probabilities with two different values or ratings?

I would like to know how to find three probabilities of two values.... Specifically...I want to know the three soccer venues (HOME DRAW AWAY) proabilities with two ratings... Example: I have two ...
0
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0answers
21 views

Can I determine whether two quadratic slopes differ significantly?

I know that there are ways to compare two linear functions to determine whether the slopes of the functions are significantly different. However, I'm wondering whether there is any way to compare ...
0
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1answer
24 views

Determine whether something is “significantly maximal”

The problem: I have a measure $D_i$ that quantifies how well a single target "feature" can be predicted from a set of (other) features $i$ (similar to an AUC). $D_i$ is computed based on a set of $n$ ...
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0answers
15 views

Odds of a team winning a sports match given full history

Assumptions: The teams never change The teams don't improve in skill The entire history of each team's performance against some subset of other teams is known For example: I have a long list of ...
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0answers
43 views

Significance testing of categorical variables - is chi squared as good as it gets?

I am testing categorical variables for significant relationships, 5 age groups and 3 answer options (yes/no/don't know). Is there a test which will specifically tell me if e.g. age group 1 is ...
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0answers
28 views

Statistic T-Test & T-table

Hi can anyone help me with this question . Thank you! I know that for part (a) degree of freedom is 13. But how do I use the t-table to answer (b) and (c). The t-table is below
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0answers
11 views

statistically analyse pass rate of test in different locations

I'm looking to analyse some data and as it's been a long time since my statistics days I'd like to know which area of statistics my problem lies. Lets say I have a number of different driving ...
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1answer
28 views

backward selection but regression coefficients not significative? [closed]

I'm running a logistic regression with backard selection method. I get coefficients with p-values>.10. Here's an example: ...
2
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0answers
19 views

Should I check the z-score if the p-value of Local Moran's I is significant?

The dataset I'm using contains income data per area. The values are not normally distributed as shown in the following diagram. Global Moran's I indicates significant spatial patterns and Local ...
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0answers
13 views

Probability that difference between demand for two skills in a population sample is due to chance

I am trying to measure the demand for two skills in group of companies that are hiring software developers. One skill might be e.g. Java and the other e.g. C++. If out of 100 companies, 30 report they ...
0
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1answer
16 views

Proportion Comparison

I have data from baseline and end line surveys. Baseline was conducted before intervention in children and end-line was conducted after intervention in the same population. Study population is same ...
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1answer
29 views

Statistical analysis of variable data

I have the statistical research data. I have 6 treatments with 3 boxes for each treatment. I am raining on the treatments every week and collecting data. The data is variable within boxes and also ...
0
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0answers
28 views

difference between machine learning and stastitical technique [duplicate]

Is there any difference between machine learning and stastitical techniques. I have searched a lot some researchers say that there are some overlap some are saying there is no difference.Can you give ...
1
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2answers
56 views

Comparison of machine learning algorithms

Suppose i have taken 8 machine learning algorithm which is used researchers more frequently.I have applied these 8 machine learning algorithm over 8 datasets which is publickly available on internet. ...
0
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1answer
13 views

How to compare four sets of experimental data and decide if the differences are significant?

For a school science fair project, my daughter randomly divided a population of subjects into a control group and three experimental groups. We recorded the time each subject took to perform a certain ...
1
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1answer
19 views

Test for non-uniform sampling from a sequence without replacement?

I have a dataset that essentially amounts to a sample of K unique elements from an ordered sequence of length N. I believe that elements are more likely to be sampled from certain portions of the ...
3
votes
1answer
69 views

Interpreting results of chi-squared

Situation: A/B test of a single website change on a landing page. Alternating visitors to the landing page are shown a variation. The goal is to convert more visitors into customers. With data that ...