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Questions tagged [differences]

The process of taking the difference between two values to achieve desirable statistical properties. e.g. paired differences t-test, differences between time points in an AR(1) model, and difference-in-differences causal impact analysis.

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Statistical test to show differences between two categorical datasets

I have two categorical datasets that I would like to compare against each other, but I'm not exactly sure which test to choose and how to go about it. Both datasets show the number of cases for 8 ...
lgu93's user avatar
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1 answer
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How to compare cases and controls after adjusting for age differences?

I have a dataset in which I have different measures (a, b, c) and two independent variables: D which is an independent binary variable representing cases (1) and controls (0), and age is another ...
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What is the difference between a one sample t test of the difference between two groups versus a two sample t test comparing the two groups?

Let us say that we currently have two independent groups $G_1, G_2$ with equal sample numbers $n_{G_1} = n_{G_2}$ and may not have equal variances $ {\sigma_1}^2 \neq {\sigma_2}^2$. If the statistical ...
Syuma's user avatar
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Getting relative measure of difference between two numbers - Reference (close to) zero

I'll be writing a program that compares two numbers and based on how different they are, perform, or not perfom an action. It would make sense to have one formula to get a standardized measure that I ...
Lucas Johnston's user avatar
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Measuring treatment effect when only half the the treatment group appear affected

I have data for a set of customers divided into treatment and control, where the objective is to check the impact of treatment on customer’s bank balance. To this purpose, I computed the percentage ...
Nibbles's user avatar
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What is the distribution of similarites between 2 iterations of a binomial variable?

Suppose I have a binary vector $v$ of dimension $n$ with $np$ entries set to $1$ and $n(1-p)$ entries set to $0$ (where $0 \leq p \leq 1$, and $q:=1-p$). Suppose I then generate a random vector $w$ by ...
magnesium's user avatar
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Which test do I need for testing differences in two populations?

I would like to compare the different variables in a life table of two populations and check if the differences are significant. However, I am totally unsure which test is appropriate. For example, I ...
Octtta's user avatar
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How to calculate reliability of difference scores?

I am trying to calculate the reliability of a difference score. Specifically, the data have, for each participant, scores for 10 items in Condition X (1s and 0s), as well as 10 different items in ...
Altair555's user avatar
2 votes
1 answer
68 views

Is there a formula for the 95% confidence interval for the Skellam distribution or difference of two Poisson r.v.'s?

I have two independent Poisson random variables and want to assess the confidence bounds for X - Y. I know there is a closed form solution for Poisson confidence bounds, but need the difference. Can I ...
Bluegreen17's user avatar
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How to compare if multi-class outputs are different?

I am testing different multi-class (16 classes) classification models (ANN, DNN, DL, and so on) and the overall accuracy varies from 0.75 to 0.92. Despite that 0.92 is greater than 0.75, is there a ...
aldo_tapia's user avatar
2 votes
1 answer
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How to calculate mean difference for effect size calculation?

For a two-sample effect size calculation on paired data (or a one-sample test on differences), does it make sense for an effect size to be negative for a hypothetical % increase of a mean? I’m doing a ...
Nate's user avatar
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Statistical difference between very small distributions

I am evaluating machine learning classifiers with 4-cross validation due to very small dataset. Is there a way to determine if a classifier is better (other than F1 averages) from only 4 performance ...
dibil08's user avatar
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22 views

How to model a difference score for cross-sectional, hierarchical survey data

What is the best way to model a difference score that is based on cross-sectional survey data, while also taking into account the hierarchical structure of the survey data? I have the following survey ...
Alina's user avatar
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6 votes
1 answer
175 views

A time-series where the average of the difference depends only on the interval

Consider a time-series: $\{X_1,X_2,\ldots,X_T\}$. Then, we can think of the difference like $X_{t+r}-X_{t}$, where $r$ is an integer. Here, I am wondering whether there is any time-series process that ...
MinChul Park's user avatar
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Error between average of averages and true average [closed]

It is known that the average of averages can yield an incorrect result as compared to the true average. The classroom example comes to mind: if the test results of class A is [50, 60, 100], class B is ...
saru's user avatar
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Can I test for a significant difference within one variable?

I collected microplastics falling on an island in a year. The types of microplastics are fiber (F) and miscellaneous (M) particles. I want to know if the number of each that fell are significantly ...
NickW's user avatar
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Improving an ARIMA model by eliminating AR/ME terms

I've come over the following two statements to manually improve the fit of an ARIMA model by changing its parameters $p,q$. If the AR coefficients sum to nearly 1 and suggest a unit root in the AR ...
Daraan's user avatar
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1 answer
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Independent Variable vs. Dependent Variable in Statistics

Following are the definitions of independent variable and dependent variable I found on the internet: <1> In statistical modelling, the dependent variable is studied to see if and how much it ...
Vinay Sharma's user avatar
4 votes
1 answer
128 views

Inverting diff() and BoxCox() in R

i'm doing a project with a non-stationary time series. i used BoxCox trasformation and differences to make it stationary ...
Carmine's user avatar
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2 votes
1 answer
2k views

One-way Table vs Two-way Table. What’s the difference?

The following is the definition representative of the definitions if you google the difference between the one-way and two-way table: Sometimes we talk about data tables in terms of independent and ...
Vinay Sharma's user avatar
6 votes
1 answer
110 views

Expected Value of the Difference Between the Powers of Two Randomly Selected Numbers From a Standard Normal Distribution

My question is similar to (and an extension of) this one. I select two values ($i$ and $j$) at random from a standard normal distribution. What is the expected value of $|x_i^n-x_j^n|$ for all integer ...
David Moore's user avatar
1 vote
0 answers
58 views

Transform Second Difference Predictions from VAR model back to levels

I am currently working with a VAR model in R using the second difference of some variables (it only becomes stationary after differencing twice). So far I'm trying to see if the model fits one of the ...
hnsby's user avatar
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1 answer
34 views

Train Test leakage

Imagine the following dataset. 1 --> Person buys this product sometimes 0 --> Person never buys this product: ...
Tarquinius's user avatar
1 vote
2 answers
722 views

How does the Bayesian Information Criterion work for model selection? [closed]

I am aware that we can use the BIC values from different models in order to determine which model predicts the data best. However, I'm a little confused about the criteria used to determine which ...
john connor's user avatar
2 votes
1 answer
162 views

Joint posterior distribution of differences

I have data $x_1,...,x_n$, $y_1,...,y_m$ and $z_1,...,z_p$ where $$x_1,...,x_n\sim N(\mu_x,\sigma^2_x)$$ and $$y_1,...,y_m\sim N(\mu_y,\sigma^2_y)$$ and $$z_1,...,z_p\sim N(\mu_z,\sigma^2_z)$$ Now let'...
John Smith's user avatar
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17 views

Relationship between std dev of difference of 2 random samples of a distribution and the std dev of the distribution

I am studying the analytical variance of a clinical test. In published work I observed two things: 1) when looking at a particular patient, the std dev of repeated replicates was 11.5 points. 2) when ...
Ian's user avatar
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2 votes
1 answer
32 views

Bootstrapped difference test with smaller subsamples

Question How do I perform a bootstrapped difference test when my bootstrapped sample sizes are smaller than the original sample sizes? Typically I would do this by taking $p = \frac{\sum_{i=1}^{B} t_{...
David McKnight's user avatar
4 votes
3 answers
668 views

How to properly explain a delta between 0.10 to 0.05 in proportions

Assuming I have proportions for clicks to impressions of 0.10 for p1 and 0.05 for p2. This is equivalent to 10% and 5% click through rate. One way is to say that p1 is 5% higher but can we even say ...
Roger Steinberg's user avatar
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127 views

Can the chi-square statistic in Kruskal-Wallis test be compared to determine the most appropriate to distinguish the groups?

I have a dataframe in R which format is similar as follows: v1 v2 v3 group 1 3.5 100 a 3 5 200 a 10 5.5 150 b 8 7.5 210 b 4 4.5 300 c 9 2.5 200 c ... My ...
X W's user avatar
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Difference or similarity in latent variables or SEM models

There are five latent variables (three independent and two dependent) which constitute a PLS-SEM model. A single survey was conducted; however, the questions were asked twice to the same participants. ...
tmihaly's user avatar
2 votes
1 answer
137 views

Wilcoxon Signed Ranks Test for relative differences

Is it correct to use the Wilcoxon signed ranks test for relative differences $\frac{Wx-Wy}{Wy}$, instead of absolute differences $Wx-Wy$? In some cases the relative difference is more relevant, for ...
gubi's user avatar
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1 vote
1 answer
126 views

The distribution of the difference between two correlated non-central t distribution

Suppose a binormal population $\{X, Y\}$ with means $\mathbf{\mu} = \{\mu_1,\mu_2\} \ne \{0,0\}$ and covariance $\Sigma= \sigma^2\begin{bmatrix}1 & \rho\\ \rho &1 \end{bmatrix}$. Let $S^2$ be ...
Denis Cousineau's user avatar
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449 views

How to test for difference between two GLMs (generalized linear model) in R?

What are appropriate tests for determining whether two GLMs are statistically significantly different? AIC and BIC is not an option because I am not trying to determine parsimony. If it were regular ...
Candice's user avatar
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0 answers
103 views

How to determine if a relative difference is "big"?

I have two columns with the percentage of a certain variable, each column represents a different year. I calculate the relative difference in each category and I want to determine if this change is ...
esfera's user avatar
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166 views

Is it possible to use descriptive statistics to make conclusion about "differences"?

Here is the question that bothers me for a long time. I used an example to describe my question. For example, if I asked the same participants to answer the two questions: Q1) do you think that other ...
user13966876's user avatar
1 vote
0 answers
29 views

Crude difference vs effect size

Let's assume I have two groups of animals with the following weights and the average difference of 8 kilograms: Could you explain in layman's language, how the calculate difference differs from the ...
st4co4's user avatar
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3 votes
1 answer
464 views

Percentage change of interval data

My understanding is that the percentage/relative change is applicable/meaningful only with ratio data, and not with interval data. Can you confirm it is right, or correct me if it's wrong?
lee27's user avatar
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4 votes
1 answer
97 views

Sample size calculation in a clinical trial

I'm doing a clinical trial and I'm comparing a certain number before treatment and after treatment. I recorded the numbers for each patient before treatment and after treatment and take the difference(...
user10386405's user avatar
2 votes
1 answer
446 views

Which statistical method can be used to compare the values of the same variables measured from different views?

I got a biological data set, where I need to run a statistical analysis on. The data was created on a mass spectrometer and contains the intensity values for around one hundred lipids. The analysis ...
Tony Hauptmann's user avatar
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0 answers
66 views

Test which time series is closer to zero

I have two time series, A and B, which represent reactions of subject A and B to a certain medication measured at different point in times. I want to formally test that the reaction of patient A is ...
user9875321__'s user avatar
1 vote
2 answers
1k views

Taking percentage difference b/w average of values vs taking average of individual percentage differences

I have two sets of data points: List A [x1, x2, x3...xn] and List B [y1, y2, y3...yn]. If I were to calculate percentage difference between the two sets, what would be more accurate: a. Taking ...
Jatin's user avatar
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1 vote
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R or Excel: Calculate difference between dates [closed]

I have a list of course completion dates (person, start, end) in the following format (exemplary): Person X || Sept 21, 2021 06:30 PM || Sept 21, 2021 06:50 PM Now I'd like to calculate the overall ...
Lafayote's user avatar
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0 answers
816 views

Time-Series Analysis versus ODE parameter estimation -- why does one use first differences (stationarity) and the other does not?

This is kinda a tricky question, because it crosses disciplines. But I looking at the difference between time-series analysis in statistics, versus fitting parameters to ordinary differential ...
krishnab's user avatar
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1 vote
1 answer
2k views

How is standard error affected by multiplication?

If I have some measure, suppose the difference of two means, and then I multiply it by 100; how will the standard errors be affected? Will they be multiplied too? or will they be completely different?
Claudio Laudani's user avatar
0 votes
2 answers
679 views

Retrospective cohort study and case control study

What study would best suit looking at the association between low birthweight and later academic performance? Note - 1000 low birth weight children and 3000 normal birthweight children were included ...
Ljones's user avatar
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2 votes
2 answers
643 views

Differencing estimator in two-way fixed effects model

Consider a simple linear panel regression model with two-way fixed effects: $$Y_{it}=\alpha_i+\mu_t+X_{it}'\beta+u_{it}, \quad i=1,...,n, \ t=1,...,T,$$ where $n$ and $T$ represent the total units in ...
Rico's user avatar
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0 answers
50 views

how to treat values that evaluate to negative infinity with computing a percent reduction

A main limitation for reporting or measuring a percent reductions is having zero in the denominator. For example, if one was counting data on paired subjects and then analyzing the effects of some ...
cn838's user avatar
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2 votes
1 answer
281 views

If B is backshift operator, then how to calculate 1/(1 - B)?

We have known that: when |r|<1, (1−r)^-1 = 1 + r + r^2 + r^3 + r^4 + . . . But for 1/(1-B), since the coefficient of B is 1, the power series 1 + B + B^2 + B^3 + . . . can not converge. In my ...
vegetabletina's user avatar
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1 answer
50 views

Should i make correlation matrix of (1) first difference logarithm, (2) logarithm or (3) the natural numbers?

I am currently working on a project where I am looking at how prices are affected by changes in the exchange rates. For an example, I want to see how a change in my currency (Norwegian Kroner) affects ...
schix's user avatar
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1 vote
0 answers
27 views

Developing intuition on what difference between consecutive points means

As an example, let's take var_a and var_b: var_a <- c(0,10,10,9,12,10,10,0) ...
Ray's user avatar
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