# 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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
50 views

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### 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 ...
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 ...
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 ...
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 ...
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 ...
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: ...
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 ...
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?
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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### 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 ...
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-...
8k views

### What is the difference between univariate and multivariate time series?

I have the following time series data: ...
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?
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 ...
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 ...