Questions tagged [differences]

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Concise clear explanation Confidence Intervals for Differences & Sums

I understand confidence intervals for means and proportions, but just don't see how it works for differences and sums. I don't even fully understand its purpose or why I should care. I've seen two ...
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26 views

Calculating interclass correlation but with different observer experience

I have tried finding an answer to the following question both here and using PubMed and google but without luck. I have been asked to calculate the intraclass correlation coefficient from the ...
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1answer
20 views

Summing up differences of means

Say I have four treatments with two factors: Treatment 1: Factor A Treatment 2: Factor B Treatment 3: Factor A and B Treatment 4: no factor (Control) I can now use anova to detect interactions. I ...
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1answer
36 views

Model selection based on the closest fit to another model

For each subject I have two measures, let's say $X$ and $Y$, that correspond to the same measurement but each from a different measurement device. In theory we assume that ideally these two ...
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1answer
25 views

Statistical test for preference data through average differences or is other method more suitable?

I need your help. I'm designing a questionary and there I want test which version the people prefere. Which of the following methods is better and which statistical test for significance in each ...
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1answer
72 views

derivative of mathematical expectation [closed]

As we know,if x is a random variable, we could write mathematical expectation based on cumulative distribution function $(F)$ as follow: $E(X)=\int[1-F(x)]d(x) $ In my problem, t is a random variable ...
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2answers
24 views

Comparing Closeness Between Two Counts

I need to count the number of cells in several pictures. Since the picture is not totally clear, I let two people to count for each picture. I need to compare to see if the two counts are close enough ...
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0answers
50 views

Probability that one positive random variable is greater than another independent and identically distributed positive random variable

Suppose I have the following random variables $X_{0} \sim f(x)$ and $X_{1} \sim f(x)$ are independent. I want to know the probability that $X_{0} > X_{1}$. So I think I want to find: $$ P(X_{0}>...
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8 views

properties of the disurbance term ε in the difference regression

let's say we a model $$Y_t = β_1 + β_2X_t +u_t$$ assume that u's are in fact serially independent, and that $u_t= ρu_{t-1} + ε_t$ what are the properties of the disturbance term $ε$, if we used the ...
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46 views

Is the difference between two samples of two distributions a sample of the difference of the distributions? [closed]

My question is as follows. Suppose you have two variables $X$, $Y$. If I pick a random sample $x$ from the distribution over $X$ that has probability density function $f_X$, and another random sample $...
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19 views

Comparing predictability of outcomes across leagues

From time to time I encounter newspaper articles with titles like “Unpredictable English Premier League Keeps Us Guessing”, which make claims about the difference in predictability of outcomes across ...
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1answer
41 views

Why do I get completely different results when subjecting my data to a t-test in different ways?

I subjected my data to a t-test in two manners of which I expected the same output would be generated. It turned out it is not so. Now I would like to know wherein the profound differences in the data-...
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1answer
19 views

Two formulas giving slightly different output

I am struggling to find a proper explanation why the two methods that I use for finding the difference in EXCEL are giving me two slightly different numbers. The idea behind the task is that we have ...
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24 views

What is the relationship between negative autocorrelation and first differenced outliers?

I am currently working with economic data and I am trying to model my dependent variable using several macroeconomic independent variables. When I tried linear regression on the data, I got a high R-...
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48 views

Are Box-Cox and differencing redundant or complementary?

I was always under the impression that differencing and Box-Cox were two ways to achieve the same goal: Making a time series stationary so that it can be modeled using an ARMA process. However, ...
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23 views

Time-invariant covariates & first-difference estimations

The intuition behind first difference estimates (FD) is to remove individual unobserved heterogeneity from the estimation. However, I'm not sure if I should not include time-invariant covariates to ...
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25 views

When to choose difference versus log ratio for expressing variables relatively?

Oftentimes I wish to express one time series (say) relative to a second one. The two obvious candidate approaches are to take their difference or their ratio. Whereas the difference is symmetric with ...
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1answer
23 views

What is the relation between the effect size and correlation?

Correlation refers to the degree to which a pair of variables is linearly related. The effect size quantifies some difference between two groups (e.g. the difference between the means of two datasets)....
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18 views

Subtraction between features before performing PCA and training a classification model

In my dataset, I've created moving averages for historical indicators. Is it pertinent to perform subtraction between those moving averages before PCA? My stats/calculus feeling: as PCA is a ...
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6 views

How to determine the percentage difference between two quantities associated with uncertainty measure

Say I have two quantities 10 ± 2 and 12 ± 3 (uncertainty is standard error). How do I determine the percentage difference between them? Or should I determine it at all (There is no meaning to do it in ...
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72 views

How to interpret Emmeans results

I have used the emmeans() package to calculated the difference between the difference of estimated marginal means. I did this by first calculating the EMMs of location|treatment, and then the ...
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0answers
16 views

First or second difference or log for simulated real GDP data?

For a paper I need to use simulated real GDP data to regress this on average income mobility (how much more the next generation earns). As a hint the assignment indicates that the STATA code for a ...
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1answer
334 views

What is the relation between ELBO and SGVB?

Evidence lower bound (ELBO) can be maximized, so that to find the most appropriate approximative distribution of the target distribution, which is equivalent to the minimization of the corresponding ...
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1answer
118 views

What is the difference between belief propagation and loopy belief propagation?

Belief propagation (BP) is an algorithm (or a family of algorithms) that can be used to perform inference on graphical models (e.g. a Bayesian network). BP can produce exact results on cycle-free ...
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88 views

What are the differences between Bayesian networks and hidden Markov models?

Bayesian networks and HMMs are both probabilistic graphical models and they are both represented by DAGs. What else do they have in common? What are their differences, both in terms of architecture ...
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24 views

What is the difference between “paired” and “unpaired” versions in Wilcoxon's test?

Statistical tests can e.g. be used to decide whether to accept, reject or fail to reject the null hypothesis (the status quo). There are (apparently) two variants of this Wilcoxon's test: paired and ...
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11 views

Method to compare difference in average treatment effect between 2 subgroups and then between two study arms? Difference in differences for RCT data?

Essentially I have an RCT with 1 intervention arm and 1 control arm. Within each arm I have 2 sub-groups I want to compare the average treatment effect (drug users and non-drug users) for a binary ...
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39 views

Interpretation of regression coefficients: second-order differencing

Main Question: How are the coefficients of the second-order differenced explanatory variables to be interpreted? (See the attached screenshot of my result.) Analysis framework: I examine the ...
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47 views

Calculate Percent Change after running Paired Samples T-test

I have two measurements pre and post. I ran a paired samples t-test to determine if a statistically significant difference exists between pre and post. I would like to report the Percent difference ...
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15 views

Testing difference of cumulative/integrated quantities of time series?

I am new to time series data analysis. I wonder how would one test the statistical significance of the difference between integrated quantities (area under curve) from different time-series curves? (...
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1answer
16 views

Compare the progression in multiple groups with different starting points

I am working on a project where 8 municipalities have participated in a program, in which they received consultancy on how to restructure the social sector. As a part of the program the municipalities ...
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24 views

Two-dimensional difference test

Suppose I need to find out whether both the average height and the average weight of a person in two populations are the same. Is there a standard extension of the difference test in two dimensions? ...
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1answer
25 views

How to interpret normalized difference score?

Lets say you have 2 variables, reaction time (RT) on an easy task and reaction time on a hard task. I've seen papers calculate a normalized difference score using the following: $$ Z = \frac{RT(hard) ...
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11 views

Difference of Rates in ECM

I am setting up a model to predict something using Error Correction Model (see pic. to get a general view about the model itself). Some of my $X$ variables are the interest spread between the A and B ...
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2answers
164 views

Standard Error of the cumulative value for time series

I have two time series, as in the picture below. The data was gathered experimentally. A practical example could be a measured mass flow rate, where I measure the mass flow rate over a certain time ...
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1answer
33 views

Would relative or absolute differences be more meaningful in this case? Why?

I 'm involved in a study where precentage values of carbon were take beneath between two adjacent fields. The adjacent fields differ by the vegetation cover (X, Y). Vegetation X is novel (planted 10 ...
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25 views

Comparing statistics over win/loss

I have data from a league over a season. The season was conducted as a round robin so everyone played each other. Each game was a best of 5 so at the least a game produced 3 matches and at the most ...
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30 views

How to test whether the mean of an observed time-series is statistically different from the mean of the predicted time-series?

Let's say I have an observed time-series from $y_1,...,y_T$, as well as an predicted time-series $\hat{y}_1,...,\hat{y}_T$. I want to test whether the mean of observed values $\bar{y}$ is equal to ...
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2answers
229 views

When to use raw (not relative) change vs. absolute change in a T-Test?

Suppose I have students 1 through 100 predict their test scores prior to taking a test. After the test, I record their actual scores, so that the head of my data table looks like this: ...
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1answer
32 views

Inferential test for differences in frequencies between groups?

I would like to have your suggestions regarding the kind of statistical analysis that would fit the nature of my data. Participants have seen 12 videos, in each of which an emotion was conveyed and ...
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1answer
2k views

What's the difference between an ecological study and a cross-sectional study?

What's the difference between an ecological study and a cross-sectional study? And could you provide an example?
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34 views

property about the standard deviation of 2 r.v.

If $X,Y$ are $\geq 0$ random variables, how to demonstrate that: $$2*Stdev(X) \leq Stdev(X+Y)+ Stdev(X-Y) $$ $Stdev$ represents the usual standard deviation.
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34 views

Individual differences in response time (RT) - searching for the right test

Given a distribution of response times to different categorical variables, what's the best way to test for individual differences? or more specifically: There are 100 people pressing buttons in 10 ...
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27 views

Normality in multiple regression after using first differences

I´m running multiple regression and after using first differences (as the only method which was succesful with correcting autocorrelation) my model has non-normal reasiduals. As you can see on . P-...
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1answer
8k views

What is the difference between univariate and multivariate time series?

I have the following time series data: ...
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43 views

Lag operator calculation(differencing) with polynomial trend

I am trying to show that ((1-L)^n)t^n = n! I have tried to simplify the calculation using hypergeometric series but it did not work out. Could anyone give a hint about this?
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25 views

What can the differences in slopes tell me?

I ran regression models on two sets of data, and their plots looked parallel, so I ran a t-test on their slopes and they are indeed different. I'm wondering what I can quantitatively take away from ...
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2answers
1k views

What's the difference between a descriptive statistic and a test statistic?

In the Wikipedia article about test statistic it is written A test statistic is a statistic used in statistical hypothesis testing. A hypothesis test is typically specified in terms of a test ...
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352 views

What are appropriate post-hoc tests for a negative binomial regression to explore pairwise differences in R?

We are trying to identify the pairwise differences using an equivalent to Tukey which we assume cannot be used.
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1answer
39 views

Assumption of independence of two correlations for the purpose of a statistical test of the difference.

I'm having a bit of difficulty grasping the concept of 'independence' for the purpose of testing whether two correlations significantly differ from one another (Zou, 2007). Consider the following ...