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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36 views
How do I prove that my results are significantly better in this situation?
I have a test suit for an optimization problem with 270 problem instances. For all these instances I have a lower bound and a single solution of another algorithm. I do not own this algorithm and am ...
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0answers
22 views
Difference between chi statistical methods (pearson/likelyhood/linear-by-linear)
Can someone briefly explain the differences between these three tests? When would you use one over the other? Which tests are associated with a test of independence, homogeneity, or goodness-of-fit?
...
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1answer
39 views
Chi squared test of homogeneity
Suppose you want to test the null hypothesis:
H0: p1 = 0.65, p2 = 0.27, p3 = 0.01, p4 = 0.05, p5 = 0.02
to determine whether a population's distribution matches the proposed proportions. You ...
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3answers
51 views
Area to the right or left when computing test statistic
Can someone generally explain when the area to the right or area to the left is sufficient in solving a statistical problem (using z, t, or chi)? For example, in a chi-squared problem, if we're ...
1
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1answer
69 views
Multiple hypothesis testing and F tests?
Does the multiple hypothesis testing problem apply to the calculation of an F statistic for joint significance? It seems to me that the more variables you are including in your test for joint ...
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0answers
54 views
One way ANOVA and Duncan's test
I'm working on a program for statistical calculations.Always have two sets of data...
I calculated all the other values from ANOVA and Duncan's test:
SS Effect,df effect,MS Effect,SS Error,df ...
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0answers
32 views
Whats the biggest difference in calculating a simple regression model with/without a constant term?
I have calulated an OLS with and without a constant term. However, besides that the values are different I haven`t really found anything valueable?
Therefore my question is:
Whats the biggest ...
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2answers
27 views
Hypothesis / Statsitical significance between continous variable and dependent binary variable
Sorry I am a stats newbie, I understood that I can use the search feature, I tried to search but I am afraid that I am not using the right terms and the results returned are not quite relevant to my ...
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0answers
38 views
Evaluate Quantile Regression results and t-stats at different levels.
I have a few questions regarding quantile regression and how to interpret the results. I have several independent variables and I want to figure out which combination of variables have the highest ...
0
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1answer
41 views
Finding value of residual
Consider the LSR line: y = 1158.86 - 5.54x
A researcher sought to examine the effect of average teacher salary on the average (total) SAT score. The data, measured at the state level so 50 ...
1
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0answers
47 views
Comparing sets of non-normal distributions
Apologies in advance if this question seems trivial -- I am a biologist and have little experience in statistics.
I have six non-normal distributions (they're positively skewed): three are replicates ...
0
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0answers
20 views
Dependent and unbalanced sample size
I have a dosimetric data from a radiotherapy planning for (n=21) patients. For each patient, a treatment plan was simulated in treatment planning system by changing the x,y,z parameters of the ...
-3
votes
1answer
62 views
How to find mean and standard deviation based on a given confidence interval?
If a 95% confidence interval for a population mean ranges from 200 to 240 (that is, LCL=200 and UCL=240). Then, the computed numerical values of sample mean, $\bar{x}$, and sample standard deviation ...
1
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1answer
57 views
How to interpret a non significant independent variable?
I conducted a regression analysis using R's lm() function. One of the independent variables shows no significance (p = 0.89), which contradicts the hypothesis that is should have a significantly ...
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1answer
27 views
Validation for ANOVA question
Can someone help me validate my answer to this question:
My answers come from the first row, where the significances are 0.0002,0.0011, and 0.0005, respectively. Since they are all below 5%, then ...
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0answers
78 views
t-statistics of mean using Newey-West standard error
I have seen that in several papers, where the aim was to evaluate the performance of a certain investment strategy, they use t-statistics to test for significance in the results. However, this seems a ...
2
votes
3answers
65 views
Population with known distribution (not normal) versus small sample
I have a complete population consisting of 6587 individuals (genes) and for each individual I have a distance value. These distance values are not normally distributed.
I'm interested in determining ...
24
votes
5answers
952 views
Regarding p-values, why 1% and 5%? Why not 6% or 10%?
Regarding p-values, I am wondering why 1% and 5% seem to be the gold standard for "statistical significance". Why not other values, like 6% or 10%?
Is there a fundamental mathematical reason for ...
3
votes
1answer
124 views
Significant difference from regression confidence intervals
I have a question about statistical significance in relation to confidence intervals from linear regression. I'm obviously far from a stats expert, and I've been searching for the answer to this, ...
2
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0answers
17 views
Time variation in coefficients
Given $x_t, y_t$ ($t=1,\ldots,240$), I want to estimate $y_t = \alpha_t + \beta_t x_t$ and test $H_0: \alpha_1=\ldots=\alpha_T=0$. It is crucial to allow for time variation in the regression ...
2
votes
3answers
49 views
Evaluate statistical significance of difference between outcomes of tests
I have 400 patients and I apply 4 tests to all of them. This gives me a number of positive and negative for each test. I want to compare the tests 2 by 2 to find out if there is any statistically ...
-2
votes
3answers
71 views
Determining if awards are fair
Imagine a population of people where $x\%$ have blue hats and $(100-x)\%$ have green hats where every year some people are awarded prizes. The rule is that everyone should have an equal chance of ...
3
votes
2answers
220 views
Test a significant difference between two slope values
The data I have are a regression slope value of y~time, a standard error, an n value and a p value, for a particular species in two different areas. I want to check whether the the regression slope ...
3
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0answers
63 views
binomial test for testing significance of classification very sensitive to hits count
I'm doing a multi-class classification task and I wonder if I'm doing the binomial test correctly since it is very sensitive to the count of correctly classified trials (hits count).
Say, there are ...
4
votes
2answers
190 views
Highly significant coefficient does not increase R²
I have a multiple linear regression with a couple of independent variables in it. Most of them are significant at p<0.001. The model has an R² of 0.83. When I add more variables, the old and the ...
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0answers
53 views
How can I calculate if there is a statistical difference?
I have a study with the following data and I would like to calculate if there is or isn't any statistically significant difference between the 4 groups:
...
2
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1answer
60 views
Is there a specific name for this formula?
I was wondering if there was a specific name for this formula and if it is involved in an established statistical process (like how chi-squared tests are for comparing observation classes or t tests ...
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1answer
54 views
Out of sample bootstrapping and significance
I am investigating the relationship between temperature fields obtained from numerical weather models and electricity demand. I am applying a PCA-based approach, i.e. I study the linear relationship ...
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0answers
29 views
Is chi-square enough to prove relationship or there is need to test for proportions?
If I test for chi-square and found a p-value <0.05, and I and can see from data that 80% of males exercise, is that enough to prove the relationship of I need to use proportions test ?
Thanks !
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1answer
31 views
chi-square test to check relationshio between season and win/loss
Given records for a team in 2 semesters Fall and Spring. We want to check if there is a relationship between the semester "Fall or Spring" and result "win or loss". Can chi-square test be used? ...
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4answers
62 views
t-test equivalent for samples, given a distribution of unknown form?
If there are two samples from a distribution whose form is not known, and which is certainly not normal, how can one ascertain the probability that, by random chance, their means/medians are ...
2
votes
2answers
62 views
Should I use Fisher's exact test for this?
I'm relatively new to statistics and I'm a little confused about which test I should be using for this problem.
Let’s say I am collecting data about responses to a book under two different conditions ...
1
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0answers
38 views
Statistical test to investigate multiple data sets whether they are independent
I had an 18 variable original data. I did principal component analysis and converted it to 6 PCs explaining 75% of the variance of original data. The I clustered the 6 PCs. For that, I first used ...
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1answer
55 views
Need help selecting appropriate statistical tests
I have several data related questions I am hoping to get answers to. I have a 4-week intervention (no control group) and all participants are given and pre and post test assessment consisting of two ...
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1answer
166 views
How to derive p-value from standard error between two group means?
Data was collected on binary variable and continuous variable. The binary variable represents two groups.
Group 1 has a sample size $n_1$ and mean $\mu_1$ on the continuous variable
Group 2 has a ...
3
votes
1answer
71 views
Assessing quality of clusters
I am running into problem of assessing the quality of clusters. In my case, I have plotted the data after determining data classes. For each class (1, 2, 3) there are two clouds that appear separately ...
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0answers
33 views
A randomized block experiment [closed]
A randomized block experiment was conducted to investigate the effect of different lighting patterns (the treatment factor) on the egg production of chickens. Extended daylight (14 hours) and flashing ...
1
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2answers
88 views
Spotting trends in time based data
I have a dataset which I need to spot trends in. The actual data refers to operation calls which take a certain amount of time to complete. My client wants to know which operation calls are improving ...
0
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2answers
63 views
Cause-Specific Mortality (or Survival ) Analysis
I am looking for the statistical test that shows the significant contribution of one factor to the overall rate (cause and death rate). Our study is about the number of people who died from year 2008 ...
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0answers
77 views
How to set the significance level in a hypothesis test correctly
I have difficulties understanding probabilities.
Let's imagine I have a test based on time series regressions and my null hypothesis is that I will pass my next exam in statistics. The test is ...
1
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1answer
101 views
How to compare similarity between two discrete distributions
I am trying to compare two temporal distributions. To give an example, consider two factories. For each factory we have a distribution of number of hours taken to produce a product. E.g. 40% of total ...
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0answers
253 views
Stata: wald test ratio coefficients from separate models
Dear Cross Validated people,
On Stata, I am using a probit model on data from a correspondece test on the labour market. The unit of observations are people, and Y=1 indicates that the individual ...
0
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0answers
43 views
Computing event rates given RR + CI and total sample size in each treatment group
I am looking at some data for the risk of mortality in patients undergoing treatment A vs treatment B and I am given the total number of patients in each treatment arm and the relative risk + ...
2
votes
0answers
59 views
Which statistical test to use?
I have acquired data from 3 different donors in which 6 different drugs were tested over a period of time. For a period of 1 week I have measured 1 parameter each day from each condition from each ...
3
votes
1answer
134 views
Test to show when diverging linear regression models are statistically different
What method will allow me to identify the values of the independent variable where two (or more) diverging linear regression models are statistically different?
e.g.
Take two simple linear ...
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0answers
28 views
Can significant relationship be used with significant difference at same time?
Usually I read about either testing for significant relationship or significant difference but can they used both to prove something? For example, assume a shop wants to compare its profits per month ...
0
votes
1answer
54 views
Testing for differences, would I use ANOVA?
I have four age groups all measuring different heights: How would I test for difference between the groups at 0.01 level of significance? Would I use ANOVA?
Also - how could I establish which group ...
3
votes
0answers
53 views
Testing for mutual exclusivity
So first, sorry if I use non-standard vocabulary, since I am not an expert. Please feel free to correct.
I would like to know if a set of genes in a patient cohort are mutated by a mutually exclusive ...
0
votes
1answer
293 views
How to statistically analyze significance with 7-point Likert scale data?
I am working on a business research paper. The hypothesis is that the sales rep influences the customer's decisions. Independent variables consist of the sales rep's: knowledge, pushiness, ...
0
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2answers
68 views
Regression by the model $y_t = β + u_t$
I have 30 data points and should calculate the residuals $u_t$ from them.
My regression model is:
$$y_t = β + u_t$$
...
