# 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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### Exercise of Hypothesis Testing

An insurance company is reviewing its current policy rates. When originally setting the rates they believed that the average claim amount was $1,800$. They are concerned that the true mean is actually ...
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### Specific questions: Statistical tests, fair analysis

Background: My dataset is small (3 to 10 values). But each set comes from 18 acquisitions of different areas of the same sample. So they would not be considered independent. But 3-10 values are too ...
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### How to report result from two-way repeated measures ANOVA?

I have conducted an empirical study as part of my master thesis. I have developed a software tool where cards can be sorted (affinity diagram) and in the study each test subject did a number of ...
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### Paired-sample t test for usability scores

I have conducted an empirical study as a part of my master thesis. Each test subject filled out a questionnaire where some questions were regarding usability of different features. What is the ...
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### Quantifying heterogeneity

I have been trying to quantify the heterogeneity of a given variable. I'd like to say that the distribution in calcite concentrations, for example, is more heterogeneous in one rock formation than ...
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### Cross-correlation significance in SPSS

How do I test the significance of cross-correlation values in SPSS? It seems there is no option for this.
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### How to verify the reliability of a survey

My question is about the reliability of the survey data (survey answers). Do you know any statistical methods for that purpose ? Maybe there are methods which use the data of the demographic questions ...
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### Confidence interval vs Significance level question

Until now I thought that the significance level and the confidence interval were the complement of each other, i.e. when some question asked me to carry out a hypothesis test with a $p %$ significance ...
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### Odds ratio for no. of hypertensives in different age groups

I have 6 age groups 18-20, 20-30, …, >60. I want to see the significant association between age and no. of hypertensives. I used Chi-square test for this and I found significant. Now can I compute ...
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### Pairwise Correlations--Multiple Comparison Correction

I have a dataset with two sets of variables defining each sample. I am performing pairwise correlations between each variable in the first set with every variable in the second set. I essentially ...
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### What kind of statistical test could help show this?

I have a log of customer call data, and would like to know what kind of statistical test I could use to test for statistical significance. Customers call with a unique call reason, and fit into either ...
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### Should covariates that are not statistically significant be 'kept in' when creating a model?

I have several covariates in my calculation for a model, and not all of them are statistically significant. Should I remove those that are not? This question discusses the phenomenon, but does not ...
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### What can I say about my logistic regression output?

I'm analyzing customer satisfaction for a certain program. My response variable is ordinal- where 0 means dissatisfied and 1 means satisfied. I have 10 predictor variables. I used Binary logistic ...
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### Significant difference between two groups in a right /wrong quiz

I did an exam, which the comment given was that my answers to two questions were too "short" or lacking… (I do not know what was lacking). I would like to learn and understand. As I remember I think I ...
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### Which statistical test to use? Paired-sample or independent-sample?

I have 1 subject rating 40 participants on the big five personality traits and other variables. these 40 participants are in 2 conditions (20 each). I want to compare whether there is a difference ...
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### Intercept significant but not the variables in GLM

I got these results from a GLM from R, but I am not sure what it means that the intercept is significant but none of my variables actually are. So is nothing really significant? Here are my results: ...
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### Sample size for Test Response Rate lower than control Response Rate

I have a question regard to sample sizes (percentage, test vs, control) when creating test experiments. When I was learning how to calculate sample sizes, we always assumed the test response rate is ...
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### When testing CAPM why is r-squared so low?

I am testing CAPM, Fama-French & Carhart-models (so a 1-factor, 3-factor and 4-factor model) for financial portfolios (60 observations). There is one type of portfolio with low R²'s. The CAPM ...
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### Specific interpretation of non-significant test considering power and effect size

Assuming a test where p > alpha and n is large enough for power > 95% at effect size d, what is the exact interpretation of the test regarding the relationship between the observed data, the real ...
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### How to compute the t-ratio at 0.05 significance level?

My statistics program plots vertical lines representing a t-ratio at 5% significance level along with its sorted parameter estimates when fitting a linear model. I don't understand how this line is ...
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### I have a non-signficiant ANOVA for a between subjects variable, but a significant planned comparison, is this allowed?

As the title states, I ran an ANOVA and have a non-significant p for a between subjects variable that I wanted to use pairwise comparisons. I designed the study though with a planned comparison ...
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### Statistical similarity on sequences

What are the methods that can be used for evaluating the similarity of the sequences? Lets say that we have three sequences; I want to be able to say that "statistically" the sequence number 1 and the ...
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### How to Analyse and predict

I'm having a set of data's, say ...
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### 2x2 factorial design minimal expected significant factors

I'm at the point of conducting a 2x2 factorial design. My adviser says that it has no use to conduct an experiment based on such a simple design unless you expect everything to be significant; 2 main ...
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### How to interpret the overall statistically significant effect of a MANOVA (In words)?

I have the following analysis: I ran a MANOVA with two DVs (both empathy scales) and an IV (gender). Now the $p$-value (.03) tells me that there is a significant difference between men and women. ...
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### Which statistical test is suitable to derive the probability of significance in difference (p-value) [closed]

Help me in finding the suitable statistical test to show the significance difference [through p-value] ...
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### The correct probability distribution / way to identify large deviations in a set of daily changes to portfolio value

I am working on a report which is being sent through to end users that should flag to them any "large changes" in the day-to-day values for the past 30 days. These values are day-to-day differences ...
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In Google's consumer survey product, they calculate confidence intervals using the Wilson score interval for the unweighted results. Does anyone know how they calculate the confidence interval after ...
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### Significance of correlation with only 11 datapoints

I am currently working on my thesis and calculating some simple correlation coefficients. I only have 11 datapoints available, but I would like to assess the statistial significance of my results. The ...
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### R2, P-value, or accuracy of model?

Which is more important when selecting a model? The R2 or the accuracy of the model? Here are 2 different models using the same data with different transformations for the Xs, the Ys are a percentage ...
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### Significance test for categorical repeated measure data

Despite my best search, I wasn't able to find any solid leads for my problem, so I thought I would share it with the community. It's a question about how to detect a difference between multiple ...
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### Highly significant positive binary IV: Interaction always positive too

I'm working on a project where the main independent variable is binary. We then interact this variable with different continuous variables. The binary variable is by far the most significant variable ...
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### Chance level for a 3-class problem

For a 3-class classification problem the theoretical chance level is 33.33%. What should be the minimum accuracy (in percentage) to be above chance level f0r a significance intervals of 5% and 1%. And ...
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### Reference on how to choose models

I wonder if there is any good and easy to understand book on reviewing on when should a particular statistical model (binomial, logistic regression, etc) be used? My background is in statistics, but ...
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### Significance test for PMCC

149 students each sat two tests. My null hypothesis is that the product-moment correlation coefficient is 1, because each test should be an accurate indicator of current attainment. The actual PMCC ...
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### Significant difference between difference scores of 2 groups on two measures?

I am investigating a discrepancy between male and female self reports of sexual experiences. The original survey consists of a female version (asking about victimization) and a male version (asking ...
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### Ljung-Box Statistics for ARIMA residuals in R: confusing test results

I have a time series I am trying to forecast, for which I have used the seasonal ARIMA(0,0,0)(0,1,0)[12] model (=fit2). It is different from what R suggested with auto.arima (R calculated ...
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### Should I use Chi Squared/Fisher's Exact Test or McNemar's Test?

Say I did a survey of 100 people asking if they eat vegetables daily. Out of my sample population, 60 say they do, 40 say they don't. Now, I also have the breakdown of males and females. Say in the 60 ...
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### How to analyze data from a 2x3 experiment where one cell is missing?

I have an experiment with two factors. The first factor, picture, has three levels: nice, ugly, absent (i.e., the picture is not presented). The second factor, information, has two levels: present, ...
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### Change in proportion - two timepoints

In the first time point - 75% (485 out of 646) of boys and 63% (350/555) of girls are in group A. In the second time point - 80% (480/600) of boys and 45% (225/500) of girls are in group A. So that ...
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### How do I find values not given in (/interpolate in) statistical tables?

Often people use programs to obtain p-values, but sometimes - for whatever reason - it may be necessary to obtain a critical value from a set of tables. Given a statistical table with a limited ...
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### How is the 95% in 2 standard deviations above different than 95% confidence interval?

Is there a difference between the two uses of 95% in: mean + 2 standard deviations (statistically significant) confidence interval
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### The result of absolute change and relative change in t test is different

My task is to evaluate the effectiveness of an intervention. In my study, there are one control group and one intervention group. There are two time points, baseline and endpoint. And I use the score ...
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### Understanding statistical significance in variance and correlation?

I have little background in statistics. For a dozen items, I have vectors of ratings for these items. I have calculated the variance, and Pearson correlation for these items (using numpy). Now I ...
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### Calculating when significance will be reached in A/B test ($\chi^2$ test of the difference between two proportions)

I'm a marketer trying to understand the math involved in A/B testing. I've come across a tool that estimates how many more samples are required to reach significance for a test that's already begun. ...
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### How do I analyze these two sets of data

I am doing a research study on self efficacy and birth month (when children enter school, if they are oldest in class or youngest). I have each of the participants scores on their self efficacy scale ...
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### Two methods of bootstrap significance tests

Using bootstrap I calculate p values of significance tests using two methods: resampling under the null hypothesis and counting the outcomes at least as extreme as the outcome coming from the ...
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### Randomisation/permutation test for paired vectors in R

I'm not an expert, so forgive me if some of the terminology is a little clumsy. Happy to provide more information where required. I have two vectors of 50 paired numeric values in R. I want to ...