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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How to find if any treatment is statistically better or worse in gene data given one standard method and 3 variations

Sorry I am a biologist and it appears am not quite confident enough for statistical analysis. I have datasets that represent different treatments on a biological system. It records how many genes have ...
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22 views

How to determine if a single variable is significantly different than 0?

I am working with data that has been reduced to values falling between -1 and 1. The formula is, "(number in tube 1- number in tube 2)/ (the sum of numbers in both tubes). Example: Tube 1 = 5 worms, ...
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55 views

$\chi^2$ tabulated value

I noticed that the critical $\chi^2$ value increases as the degrees of freedom increase in a $\chi^2$ table. Why is that?
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31 views

Statistical Significance

Our teacher told us If a test is rejected at 1% level of significance , then it will be rejected at 5% , 10% level of significance . I don't understand how does the rejection at 1% level of ...
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1answer
13 views

Regression: can I run specific models or do I need to run a full factorial model?

I am running a GEE (Generalized Estimating Equations) Linear Scale Response regression. I have 4 IVs: Time pressure and Approach as as factors, and BIS and BAS sensitivity as covariates. My DV is ...
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9 views

SPSS Binary logistic regression incoherent result after excluding outliers [duplicate]

I'm using binary logistic regression for my master thesis and after running the regression for a a few specific variables I get the following resutl: Then I created a filter to run the regression ...
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1answer
49 views
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1answer
28 views

Testing for differences between populations of individuals with binomial data

So I am trying to compare between populuations and determine whether there is a difference in count based data. My data look like this: ...
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7 views

How to estimate a chance of getting in the first positions, given previous tries?

I perform a series of experiments that return a number N that is between 1 and MAX. MAX varies between experiments. For example: ...
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1answer
33 views

What value does one set, in general, for the null hypothesis of β0 in a linear regression model?

Say there is a linear regression model to estimate Y, that is: $Y_i = B_0 + B_1X_i + u$ When testing the significance of your sample regression model the null hypothesis for $B_1$ would naturally be ...
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1answer
31 views

Is it appropriate to use t-tests to find the most different outcomes?

I have a large CSV file of spending by individuals on different drugs. I want to find the drugs with the most different spending patterns by gender. The file looks a bit like this, but with 7.5k ...
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2answers
23 views

Test Control. A longitudinal study

I have two samples of the same size, one being the 'treated' group, and the other used as a 'control' group. Each group have a different univariate variable (stress level), repeatedly observed over ...
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25 views

Figuring out which test to use

It's been a while since I've taken a stat's class and I came across a problem I need to solve. I was hoping someone could point me in the right direction. I know a question similar to this has ...
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1answer
29 views

What is a good test for comparing frequency counts between two groups?

I am looking for statistical methods used to compare frequency of observations between two groups. I have two geographical locations with data on different soil types present. for example, my data ...
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2answers
28 views

Statistical test if one sample is placed higher in rank

I have a rank array, say from 0 to 100 (0 being the smallest and 100 being the largest). If my data contains 89, 91, 94, and 98, I can say my data is significantly high in the rank. In other words, ...
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1answer
21 views

How to quantify whether the difference between two groups is relevant?

I'm sorry that I am not at all an expert in statistics, so my question may sound vague, or very easy. I have a group of people that I divide into two categories, $A$ and $B$, depending on some ...
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2answers
30 views

Test for statistical significance in performance variability

I'm analysing data collected from a call centre activity in which agents are calling prospective leads. For each call made, if the lead coverts the call is a success and if the lead does not convert ...
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8 views

looking for statistical analysis of two animals per group

I have used two animals per group and compared two groups. is there any test of statistics that analyze sample size as low as two
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1answer
39 views

How to identify variables with significant loadings in principal component anlaysis

I have following example of principal component analysis using first 4 variables of iris data set (code in R): ...
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1answer
34 views

Testing whether variance across 6 values is significantly above zero

We estimated a network via the Ising model procedure. The network contains 11 variables, and therefore 55 pairwise associations (these are called edges). We estimated this network in 6 different ...
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1answer
26 views

Scientific P Value with adjusted R Square [duplicate]

I am running Spearman correlation between 2 variables weight and freight both being numeric. The output I have received from correlation is P value - 0.00E+000 and Rank R Squared is 0.61 and which ...
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36 views

Testing for effect of covariate in nonlinear mixed model, T-test or F-test?

I am using package nlme for nonlinear mixed model. I use SSlogis self-starting model( Bates Pinheiro, 2000) for my model. ...
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1answer
10 views

calculating significance of common genes from different comparisons

we are having difficulties calculating the significance of our between-group comparisons. We did multiple differential expression Analyses of different time-points and mutations. We analysed the ...
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55 views

Is it possible to validate this claim about gun shootings and SSRIs?

We have received an interesting question on Skeptics.SE: Is there a correlation between mass-murder and use of psychoactive prescription drugs such as SSRIs? My suspicion is that this is not ...
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13 views

Significance of excess return using geometric mean

Since I am writting an assignement about a contrarian-strategy I have to test if the excess returns are significant or not. I calculated the excess returns this way: geomean(pf_returns) - ...
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75 views

Majority Voting statistical test

What statistical test would be appropriate to test whether the number of votes of a winner is significant when there are more than 2 levels? For the case of 2 levels I found this answer. But is there ...
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13 views

Determining significance of change in a categorical variable following intervention

I'm currently stuck and could do with some help. I'm designing a study to assess change in a categorical variable following intervention. Specifically I'm looking at change in attachment style (AS) ...
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1answer
26 views

Should I use repeated meaure ANOVA?

I have 5 interaction techniques (eg., interaction 1 to 5) and I have recruited 15 participants to participate in my study. Each participant interacts with each of these 5 techniques only once. I will ...
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24 views

Which test(s) to use?

I’m having a dataset that needs to be analyzed but I’m a bit worried about picking the appropriate test(s). It’s been a while since I last really used statistics and SPSS. Therefore I would kindly ...
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2answers
51 views

Relationship between ROC curve and statistical significance in comparison of two groups

My question is about any possible relationship between the significance of a comparison test (Mann-Whitney U) and the ROC curve. If the comparison test is strongly significant, should we expect a ...
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9 views

Likert score significance testing between two surveys

I have two surveys taken one month apart. They contain 20 Likert-type questions (strongly agree, agree, neither agree or disagree, disagree, strongly disagree). I have added strongly agree and ...
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1answer
30 views

Correlation Analysis of Standarized Testing Data

I need some insight on how to correctly analyze some data using correlations. The nature of the data and research endeavor is as follows: I have two independent samples of different sizes that ...
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13 views

Significance on AB testing

I did a A/B test for music generation in which experimenters compare audio files generated from same musical score with method A and method B.There are three options A better than B, B better than A ...
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10 views

Test significanct differences across segments in a Latent Class?

I did a latent class (2 segments) on a group of people, suppose the segment size is n1 and n2, and parameter for each segment is b1 (with s1 the standard error) and b2 (with s2 the standard error). ...
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1answer
26 views

Studying the distribution of the p-value?

I have two data vectors $X=(X_1, X_2, \dots, X_n)$ and $Y=(Y_1, Y_2, \dots, Y_m)$ where $X_i \overset{iid}{\sim} P$ and $Y_i \overset{iid}{\sim} Q$, and I am performing a two-sample test (i.e KS test ...
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What will be the best test to determine the significance in this study?

The project does not have a simple design. It is planned as follows: It is a longitudinal observation during 120 days in 48 subjects (with repeated measures using multiple tests); The subjects were ...
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35 views

Statistical significance / hypothesis testing for web experiment

I'm running a test where two groups of people are shown two different sets of search results or suggestions. We track what percentage of results each person is happy with. I've shown histograms for ...
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29 views

How would I determine statistical significance for ad impressions?

I'm programatically adding keywords to bid on. Some keywords will trigger ads and impressions, and some impressions will trigger clicks. Clicks / impressions = CTR (click-through-rate). Clicks cost. ...
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1answer
35 views

How to test whether a ratio is different from one using bootstrap?

I have a dataset including two groups of individuals. I get the median of a measurement (say weight) for each group, say W1 and W2 for group 1 and 2, and then get the ratio of the medians W1/W2. How ...
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2answers
32 views

US Population Hypothesis Test

I’m hoping someone can give me some tips on the test I have in mind for my data. I have data which is samples of Americans from various zip codes throughout the US. In my data I assume if someone has ...
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21 views

Regression Analysis and Conditional Expectation

I have to calculate a Expectation of some expression conditioned on something. I know alpha, Beta1 and Beta2 in the below expression. Income and Family_Size are 2 Uniform Random Variables between 0 ...
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2answers
26 views

Overall significance of multiple downward trends?

I am uncertain how to formally establish that I observe a negative relationship between X and Y in multiple sets of linked data points. I have analyzed several cells in which values of interest (Y) ...
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20 views

Testing for structural break in the covariance

I estimated a bivariate VAR(p) model and assume that there exist two covariance regime $\Sigma_1$ for the period 1 to $T_B$ and $\Sigma_2$ for the period $T_B+1$ to $T$. I am now interest in testing ...
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1answer
28 views

“Assuming that H0 or Ha is true”

The common way of indicating type 1, type 2 errors or power is to specify a hypothetical situation in which either there is or there is not an effect in the population. E.g., Given that there is an ...
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2answers
101 views

Significance in Longitudinal Data

I feel like this question has a very silly (simple) answer, so I apologize. I have a data set that only has 5 points 41.9 32.2 113.3 110.2 102.6 Clearly ...
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1answer
24 views

Simple Cox-related question regarding the LR test

I'm writing the Results section of a paper: If the LR-test for a Cox proportional hazards model is not significant, but one of the predictors is significant, does one (usually) report the covariate's ...
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1answer
30 views

How to quantify the similarity/difference between groups of selected features?

Since I have a imbalanced data to deal with, I randomly down-sample the negative data to reach balanced data for following feature selection and classification. To test feature's robustness to ...
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1answer
51 views

Are 10 experiments measuring 1 random variable “similar” to 1 experiment measuring 10 independent random variables?

I have some teammates that like to "measure everything" and want to decrease confidence intervals. I'm trying to intuitively understand where things can go wrong with this approach. Assuming a 90% ...
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28 views

How to determine how much of the variation in a binary dependent variable can be determined from a set of independent variables?

I'm working with a dataset of legislative voting results in the brazilian Chamber of Deputies. I have a list of votes (mapped as 1 and 0 for Yes and No), like: ...
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31 views

Market Basket Analysis

I am learning "Market Basket Analysis" and I need a clarification about Advantages and Disadvantages or Pro's and Con's of the "Market Basket Analysis". And some cases where actually this "Market ...