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24 views

How to show whether the average coefficients of determination from one regression technique are better than another across many objects?

I have 50,000 objects on which I have performed two different types of regression. Using cross validation, I obtained the average $R^2$ score from each model on each of the objects. So now I have a ...
0
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1answer
30 views

Is Student's $t$-test the right choice?

I have 2 patient populations taken from the same time period that underwent 2 different surgical laparoscopic procedures. I want to compare the rate of conversion to an open surgical procedure. In my ...
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0answers
16 views

Can I combine two pairwise comparisons?

I am using LMM in lmer. To find the most optimal model, I compare models of three-level with two level using ANOVA function. If it turns out that no significant difference between these two, then I ...
3
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1answer
54 views

Non-parametric version of paired t-test (Mann–Whitney U test)

I have data from 100 individuals doing a 2AFC under a control and a manipulated setting. I want to compare the means. I initially used a paired t-test. My supervisor noticed the distributions were not ...
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1answer
32 views

Which design is most appropriate?

I have data from an experiment testing a new treatment. Each subject has 4 data points, 2 of the new treatment and 2 of the control. It is like a paired analysis, but instead having 1 observation of ...
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0answers
26 views

small n: some variables are normally distributed some are not

We performed a biomechanical study, comparing an intact state to 5 different deficiency states on the same knee cadaver specimen. This was conducted on a very small sample size (n=8). My problem is, ...
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0answers
43 views

Bias-variance tradeoff in the paired t-test

Suppose we have $K$ subjects and a treatment with two levels, "Before" and "After". A paired t-test is equivalent to fitting a fixed effects ANOVA: $Y = Subject + Treatment $ It is also equivalent ...
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0answers
21 views

Non parametric anova or two non parametric ttest?

I have a statistical question about a project I recently got. We performed a flow cytometry assay on 3 different groups: controls (n=5), patients before treatment (n=5) and paired patients after ...
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1answer
24 views

Which test to use for paired, nonparametric, categorical data?

We asked a group of subjects to tell us their preferences for a given procedure, of which there were 4 choices. We then provided them with educational material and asked them again of their ...
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0answers
22 views

Comparing similarity of two fingerprint or bitvector

I have a question that's two part. 1) The first part is that I have a bit vector or a fingerprint of a digital circuit where the each bit is high if a specific structure or component exists and zero ...
1
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1answer
56 views

Paired $t$ test - Different Sample size

In testing the difference between a 'pre' survey group and 'post' survey group, I have the same sample population surveyed, yet different sample sizes (fewer respondents within the 'post' group). Am I ...
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0answers
15 views

Seeking covariates that can negate the effect size of treatment groups in an ANCOVA model

I was going to build an ANCOVA model with two treatment groups (climbed/unclimbed) and a set of 10 potential environmental covariates which may collectively remove the significance of the climbing ...
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0answers
7 views

Testing dispersion of values between condition on a group

I may have a tricky question. I have a within design where every participant is tested in 2 conditions. I want to compare the dispersion of the measure, for the two condition, with the hypotheses that ...
3
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1answer
59 views

Multi-class classification via all pairwise classifications with LDA

I have trained linear discriminant analysis (LDA) classifiers for three classes of the IRIS data and struggling with how to make the classification. Here is the procedure: For the Iris data, I have 3 ...
2
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2answers
180 views

Comparing performances during a race between 2 groups, which test should I use?

Imagine I organized a race between 2 types of ants. Type A and B. At the end of the race, I have the ranking, which looks something like : ...
0
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1answer
19 views

Nested ANOVA in SPSS / Science Education

I am analyzing student performance on a pre/post test designed to assess gains for a week long high school biology curriculum on natural selection. After comparing pre/post performance using a ...
1
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1answer
32 views

Repeated measures paired test

I have the following data: 2 conditions - experimental & control. 20 participants, each having 3 results for each condition. Like in the following table: ...
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0answers
95 views

How to report the Pairwise comparison in SPSS

I am using a Kruskal Wallis test for my thesis and want to report the results from this test. However, one of the plots from this test is a pairwise comparison test, which I do not understand. Can ...
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1answer
68 views

Comparing the performance of two teams measuring many variables once

Which statistical tools are best suited for this problem: Team A goes and measures 3 magnitudes in 200 locations (let's imagine the volume of a room, the insulation coefficient and the average ...
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1answer
45 views

How to test whether the absolute change of two paired samples different from zero

I have two paired samples. $\text{Group 1}: X_1,X_2, ...,X_n$ $\text{Group 2}: Y_1,\;Y_2,...,\;Y_n$. $(X_1, Y_1)$, $(X_2, Y_2), ..., (X_n, Y_n)$ are paired respectively. The null hypothesis ...
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1answer
35 views

Paired test for comparing boolean data

I have $n$ individuals, and for each individual, I have two measurements using two devices (device X and device Y). I know the ground truth for the correct measurement, and I can classify each ...
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0answers
44 views

Hypothesis test for comparing two F-measures

I have a classifier that classifies each sample point as positive or negative. Suppose I am evaluating it on a limited data set where I have ground truth and then computing the F-measure ...
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0answers
51 views

Comparing two estimators for accuracy using empirical bootstrap

I am trying to figure out the proper way to compare the quality of two estimators of a parameter based on data. The basic approach I've taken is to compute the MSE of the empirical bootstrap ...
3
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0answers
48 views

Interpret the pairwise comparison plot from SPSS

For my user study, I am trying to find out to what extent people prefer to move by foot. They had the option to rank their preference for 'walking', 'jogging' and 'running' for a several amount of ...
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2answers
52 views

How to compare short (9 points) time-series

I need to compare couples of time series to asses whether they are really different (eg. don't overlap) between themselves and from 0 (don't overlap zero). The easy way is to simply perform paired ...
0
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1answer
22 views

opinion poll, t test or paired test or others

Which test should I use to test the difference of monthly opinion poll? If I want to know whether the poll result of April is significantly different from March, should I use independent t test or ...
2
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1answer
47 views

Statistical paired test for relative change

Do you have any suggestions, which test I should use in order check if the relative change is statistically different than 0. I am sure that I should check the relative (fold) changes. Specifically, ...
1
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1answer
30 views

Testing for paired subjects AND two timepoints

How should I best analyze data that have "2x pairing"? E.g., N set of twins, each twin randomly assigned to active drug or placebo, then measure indicator X at timepoints A (before administration) and ...
0
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1answer
29 views

Paired difference test

I am predicting missing values by using two different methods (e.g., data imputation methods). Following I am interested to test if the predicted values, obtained by means of two different methods, ...
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0answers
13 views

R Prefmod for paired comparisons

I'm trying to use the prefmod package to analyzed paired comparisons, but unfortunately the documentation is a bit poor and the author is no longer with us. I have a survey with 32 questions, split ...
0
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1answer
32 views

Are multiple paired t-tests among 2 groups safe and effective?

Part A: Suppose I have 2 groups (pre-treatment, post-treatment) and for each subject I record 3 variables. So my rows look like: ...
0
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1answer
28 views

Lsmeans: Is this what I did?

after doing the linear mixed model with lme4, I have used lsmeans for pairwise comparison with this command: lsmeans(lmer52, pairwise~color, adjust="tukey") I am ...
1
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1answer
60 views

Paired or unpaired Wilcoxon test?

I counted the number of geese on an intertidal mudflat on 100+ days over the winter. I made two counts on each of these days: one at low tide and one at high tide. I want to know if the number of ...
1
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1answer
19 views

Test to compare an effect on a variable on a daily basis

I would like to know the effect of an external factor on the number of visits on a website during a period of 4 weeks (only search visits from Google). For this, I measured the number of visits every ...
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0answers
82 views

Is pairwise wilcoxon test a valid non-parametric alternative to Tukey's HSD test?

I am trying to identify significant differences between groups from normal and non-normal distributions. When the distribution is normal the workflow is pretty straightforward: ANOVA and after that a ...
1
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1answer
749 views

Difference between the Wilcoxon Rank Sum Test and the Wilcoxon Signed Rank Test using paired observations

I was wondering what the theoretical difference is between the Wilcoxon Rank-Sum Test and the Wilcoxon Signed-Rank Test using paired observations. I know that the Wilcoxon Rank-Sum Test allows for ...
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0answers
35 views

What statistical tests can be used on a distribution of distributions?

I have two experimental conditions, each with 20 reps (40 experiments total). In all 40 experiments a non-fixed number of sounds were recorded, and I've measured each of their durations. I would now ...
5
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1answer
76 views

What is an “Unpaired Bland-Altman plot”?

I found this quote: Unpaired Bland-Altman plots were used to check systematic or bias errors in the SPECT myocardial uptake coefficients with respect to the reference standard PET data. ...
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0answers
18 views

Using BTL2 : Can we fix the scale of the ability-scores?

Using the Bradley Terry Luce 2 model: We want to rank 41 scripts by paired-comparison (package BTL2). But our dataset is incomplete. We can generate ability scores, but the scores at the end of the ...
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0answers
120 views

How to calculate ratings/rankings from Paired comparison / Pairwise comparison of large data-sets?

As part of my graduate thesis (area: psychology) I have gathered preference data. The data includes approximately 50000 heads-up comparison between elementX and elementX. I have a total of 15 ...
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1answer
99 views

Comparing two measurement devices without a criterion measurement

I am comparing energy expenditure outputs from two devices that track physical activity in a free-living setting over 10 days. Doubly labeled water is the accepted criterion measurement for this, but ...
0
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0answers
20 views

Using orthoginal comparison for non parametric data

Can I use an orthoginal comparison with non parametric data? What about using a post hoc test with my non parametric data? I am counting the number of objects within a nucleus and based on my ...
0
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0answers
93 views

Repeated measures one way ANOVA inconsistent with paired t- test result?

I have a repeated measures one way ANOVA with a significant interaction, but no significant main effects. I ran a paired samples t-test to further my analysis and found a significant difference ...
1
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1answer
393 views

Comparing (and testing) two discrete distributions with different magnitudes

I am comparing authoritative survey data (large amount of observations) with data gained from a social network (very small amount of observations). Particularly, I want to compare population per ...
0
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0answers
318 views

Comparing frequency distributions using Mann-Whitney test

I have two frequency distributions; which each are frequency of an event. I would like to compare these distributions, and conclude that these events and conclude if these events are statistically 1 ...
0
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0answers
13 views

Repeated Measures of Dependent Randomized Conditions

I'm designing an experiment to evaluate how learnable a software tool is. The basic setup is to have $n$ subjects perform $m$ tasks in a random order, and then test whether the subjects performed ...
1
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1answer
105 views

Reporting operative effect in paired t test

I just want to make sure I have something clear in my head. When I calculate the effect size for a paired samples t-test after obtaining a significant result, I simply take the mean of the differences ...
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3answers
1k views

Paired t-test for binary data

I have one sample with n=170 and two binary variables (A,B) that can take as a value 1 or 0, where 1 counts as a success and 0 counts as a failure. What I want to know is whether the means of these ...
2
votes
1answer
116 views

Why do zero differences not enter computation in the Wilcoxon signed ranked test?

The Wilcoxon signed ranked test tells us if the median difference between paired data can be zero. The test is executed by computing a statistic, then a z-score and comparing it to a critical value. ...
6
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1answer
367 views

Relative efficiency of Wilcoxon signed rank in small samples

I have seen in published literature (and posted on here) that the asymptotic relative efficiency of the Wilcoxon signed rank test is at least 0.864 when compared to the t test. I have also heard that ...