I am working on a meta-analysis that assesses the relationship between amount of substance A in the diet and the concentration of substance A in the blood. In the identified studies, this relationship is shown as a Pearson r in the majority and as beta coefficients in a large minority. However, a few studies report

Conversion of ANOVA to Pearson r]]>

I think the data I am currently interested in is probably something like a truncated normal or beta. The data is the number of moves players take to solve a solitaire deal. The minimum number is 52. This game allows unlimited passes through the deck...

Is there a good tool for finding the best curve to fit my data?]]>

I am curious to hear if you have any checklist that you use before actually doing a regression. (i.e what do you ask yourself before performing the analysis, what kind of tests do you perform).

My goal is to assemble some basic checklist that everyone must go through before performing a regression analysis.

Best,

statoverflow]]>

I read in this article on p-values that the use of p-values is increasingly criticized in the field of clinical trials.

One of the reasons is that the 5% level is not fully meaningful.

I was interested to know if other alternatives have been proposed for clinical trials decisions.

Thanks]]>

This dataset, in which is studied the number of calories emitted during exercise on

Help! What analysis should be performed on a dataset like this?]]>

I would like to know, how to find the best regression model ?

I have different models with different variables. I would like to know which of them is the "best" to use.

The lowest AIC value is enough to determine the 'best' model ?]]>

Ideally, I would like to set the uncertainty value as the error bar for each point but the spreadsheet limits me to one error bar value for all the points. So do I list all the values, get the...

Plotting Error Bars]]>

I want to calculate the average standard deviation from my data set, but I don’t know which method will be correct.

I use an exponential curve fit on my raw data and and I get numbers with already calculated standard deviation. Per parallel experiment I have five replicates.

The resulting data set is, for example:

69,3 +/- 0,5

69,8 +/- 0,6

69,1 +/- 1,2

68,8 +/- 0,7

69,8 +/- 0,5

From these, I want to calculate the average. Currently, I have been using SD(avg) = 1/N*(root(sum(SD^2)))...

Calculating average standard deviation]]>

I am currently studying the reproduction of brown trout (salmo trutta fario) on a French river. I have at my disposal a whole series of data that I collected myself from January to the end of May.

Firstly, all the nests from 2022 have been geolocated and associated with the week of spawning, a flow facies, the presence of grass beds, the distance to the source and various other climatic parameters.

id semaine parcours source facies herbiers latitude longitude TempMoy...

How would you do ? - data on trout reproduction in river]]>

I was wondering if someone can help me out. I am currently writing my thesis and I am in the middle of data analysis. My dependent variable was not normally distributed. Hence, I log-transformed the data (log10(x+1)). I used '+1' in order to prevent the exclusion of 'zeros' in my data. Now my data was normally distributed, so I could run a simple multivariate linear regression. I was able to find out how to back transform the unstandardized coefficient using the following...

Back transformation of log transformed data]]>

Question about the normality assumption]]>

I was wondering how posters here analyze the results of regression?]]>

First, I would like to identify promising candidate RNAs in a study on 10 cases versus 10 controls. Then I would validate them in the larger cohort.

Matching in discovery nested case-control study]]>

I am trying to investigate how frogs level of aggressiveness influence their plastic responses to a more or less big opponent.

To do so, I presented an individual with a simulated opponent, representing the average type of the population, and I measured how quickly the focal individual reacted to the opponent, jumped towards it and reached it. I know from previous results that these variables are repeatable and that a latent variable ("aggressiveness") explains the covariance...

how to study the influence of personality (repeated measures) on a trait]]>

I have a question regarding sample size calculation for my research study and was not able to find an answer elsewhere.

The study compares two imaging methods and should prove that one method is equivalent to the other method in terms of geometric measurements.

The question: Each patient will provide multiple available 'samples'. Let's say the study investigates the accuracy of height measurements performed on vertebral bodies of the thoracic spine on both imaging method...

Sample size for equivalency testing with multiple 'samples' per patient]]>

Non parametric test for control/ test dataset provenient from review]]>

I have some demographic variables that I want to compare (Kendalls correlation) against the answers to a question where participants ranked the responses from 1 to 7

I have all the data in spss

I have each rank option as a variable, with a number 1-7

I am unsure how to run the the analysis however and can't seem to find anything on YouTube

Can anyone to signpost me please?]]>

I have all the data in spss

I have each rank option as a variable, with a number 1-7

I am unsure how to run the the analysis however and can't seem to find anything on YouTube

Can anyone to signpost me please?

Thanks]]>

My linear regression aims to establish a relationship between indirect collection and revenue. I did the calculation with excel data analysis and the result was 0.822, which I think is pretty good...

Choosing the best variables for a linear regression]]>

Your starting capital is 100$. And you start playing or tossing these biased coins. which money amount do you get...

Parrondo's Paradox?]]>

If I have a model with an aic of 8765 and another model reduced with two variables less with an aic of 8823.

Can I accept the reduced model with the AIC of 8823?

What is the difference between the two AICs that should not be exceeded?

Thank you]]>

The method in this paper used the regularized linear regression as its predictive model.

The point is, it has both L1 and L2 penalty terms in its objective function to be minimized.

I'm aware that Elastic Net, an intermediate model between LASSO and Ridge regression, employs both models' penalty mechanisms to overcome their limitations. And it includes the alpha parameter to control the weights of the...

What is the advantage of using the regularized regression with both L-1 and L-2 penalty term?]]>

I am identifying clusters (using latent class analysis) of respondents from a cross-national data set. After this, I will do analyses with covariates in MLwiN (multilevel structure), but I am wondering if I have already made a big mistake by ignoring the nested structure in the LCA?]]>

We are working on a stock and forex based trading algorithm. We are using statistical methods in our trading. We are already funded (but not live yet) so this is going to be a job from 1st day. We already have the idea. All of our team members will get a slice from the pie. This is a job "make happy, be happy!".

We are already invested so no need to look for an investor. What we need is great statisticians with desire and vision!

Please kindly contact me if you are interested...

Hiring statisticians for a long-term trading project]]>

I'm writing my first article on the subject of comparing our national (Finnish) lung cancer population to the Swedish and Danish to see, if there are significant differences between the two patient populations. I've gathered a total of ~600 patients worth of real world data here in Finland and I'm trying to compare it to the other Nordic populations to find some shred of evidence for the reason of our national lung cancer care shortcomings presented in a massive...

Methods for group comparison]]>

I have to write an essay at the moment and unfortunately I am stuck on a question, maybe you can help me with it.

The question is as follows: "Describe in your own words how an approximation method that determines a confidence interval for the mean of a population from a sample can be derived from the urn model. Also state a necessary requirement."

Unfortunately, I can't find any literature for this question. I believe this question is not too complicated, but unfortunately I...

Essay Question]]>

I am doing a linear regression with an interaction term which I am unsure how to interpret correctly. Lets say I have categorial variables: First variable has A and B AND second has x,y and z as categories. If I choose A and x as default/ommited as far as I know you interpret it as follows: b1x is the effect x has if A is true. If I want to know what effect the combination of x and B has I have to add: b1x + b2B + b3(x*B). This is a bit confusing as you have to add b1x in the second...

Interpreting an interaction term]]>

Before I ask my query I need to explain some basic details with respect to my study.

Design: I have a mixed factorial design 2X2x2 with two within subject factors (having 2 levels in each factors) and 2 between subject factors. I ran two analysis:

Analysis1: Mixed factorial ANOVA and found that there was was a significant main effect of all the three factors with a significant interraction effect of all the three factors.

Result of Analysis 1 (without the covariate):

Analysis 2...

Mixed ANCOVA SPSS Interpretation]]>

I am doing a linear regression including an interaction term 2x4 in size. Does this qualify for a Bonferroni correction?]]>

I am doing a regression on a independent variable. The independent variable is made up by definition of a sum of other variables in my dataset. Do I have to control for these or would that be stupid?]]>

I have been approaching PCA analysis for a few months and I have a question to ask.

We are discussing with a colleague of mine whether or not it is right to eliminate variables from our model characterized by spectroscopic data.

Plotting the first 2 principal components, these bring in our case 27.8% of the total variance of the system.

Is it a correct approach to eliminate the "Loadings" which have a minor contribution in the description of these 2 components?

In this way, the...

Delete vaiables in PCA analysis]]>

Chi square on a huge dataset]]>

I have 15 questions…. I have a set of 5 demographic questions, and then want to see if there is correlation between each of these demographic questions on the other 11 questions. For example;

- age vs confidence (Likert response).
- Age vs awareness (Likert response).
- Age vs biggest barriers (ranking)
- Etc

Kendall’s Tau and SPSS]]>

Math behind Pareto chart of standardized effects]]>

My research is about associative learning in worms, I train worms to associate two stimulus and measure their change in behavior

specifically, I expose the worms to chemicals called DA (attractive odor) or to DA together with HCl (aversive stimulus). the behavior test is called chemotaxis test, in which we measure the worms attraction toward DA, the assumption is that worms that where exposed to both DA and HCl will be less attracted to DA following the training, in this figure i'm...

choosing the right test to better answers the research questions]]>

]]>

I have conducted a two-way within-subject repeated measures ANOVA, examining a dependent variable over 5 time-points under 2 conditions. An interaction effect is revealed but when I proceed to examine the simple effects using one-way ANOVAs there are no significant effects. I am not a statistician by all means so do not know how to interpret and explain this. Any help would be greatly appreciated.

Thank you in advance!]]>

As part of an article review, a reviewer asks me to check a statistical problem but I don't know how to do it. I am doing group comparisons with widely varying numbers (10 - clinical group to 230 - control group). For continuous data, I did Kruskal-Wallis tests with Dwass-Steel-Critcholow-Fligner posthoc tests. How can I control for group size?

Also, for categorical data, I am told that Chi2 is not the most appropriate test for 6-group comparisons. What test can I use?]]>

I want to interpret my regression output of my fixed effects model. I am looking at political interest and the independet variables I include are period and cohort. All terms I included are nonlinear, I included cohort as cubic in my model. My independent variables are standardised. (I will include a picture of my margins plot and regression table).

I have a question concering the interpretation the coefficients of my model. While my marginsplot shows me that my...

Interpretation of coefficients with polynomials]]>

Post treatment groups have shown decrease in the no. of pads used, what test is most suitable for this scenario? (files attached)

Thanks a lot !]]>

I generated several normal distributions in Excel with various means and std deviations. The means did not seem to have any affect on the maximums. Herte are a few maximums based on the std devs:

StdDev Max

0.1 3.9894

0.5 0.7979

1.0 0.3989

1.5 0.2660

2.0 0.1995

5.0 0.0074

Does the max make the total area under the curve = 1?]]>

I am just starting off with Spss and statistics for my dissertation project. I would appreciate it if anybody can explain what type of test should I use for the following scenario:

My study aims to see if anxiety has an effect on the spread of misinformation online.

I am going to measure the anxiety levels of participants with the Dass 21 questionnaire which I think is an ordinal scale as it has a four point selection from 'doesn't apply to me' to 'strongly apply to me'. however this...

Help on deciding the test I need to use]]>

Here is a toy example:

Age: 0-110

Gender: Male / Female

Weight: 0-500

Height: 0-100

etc.

So its set would look like this:

0, M, 0, 0

...

110, F, 500, 100

What would be the best way to accomplish this,

Create All Variable Value Combinations For Population]]>

This is a cross-post of sorts, as I already asked a similar question here on the regression forum - I hope that's OK (if not, apologies, and mods please remove). I will use a different, psychology-focused example here, not asking specifically about regression (as maybe there's a different/better way to do this).

Let's say I'm...

Statistically comparing the strength of two different associations]]>

( I'm French sorry if english bad)

I need help on how treat my data.

For 12 weeks i have followed grass hight for 4 grassland (ABCD) . With 1 mesurement per week per grassland.

In each grassland, i have placed exclosure cage so animals cannot eat grass.

for each grassland :

- A : 9 exlcosure cages

- B : 6 exlcosure cages

- C : 6 exlcosure cages

- D : 8 exlcosure cages

mesurement where done like this :

Once a week on each grassland

5 mesurements per exclosure (each corner and middle)...

paired duos data with exclosure cages]]>

I would like to know what the conditions are for the application of a GLM.

Should we test if the response variable is normally distributed? (shapiro wilk)

Is it a problem if my variables are correlated with each other but my observations are not?

Thanks]]>

What if you population is limited. We have a population that, depending on how they define it, might be as few as 40,000. Does it matter if the population is a limited size how many you need to sample? Discussion of sample size I have seen don't talk about this.

When do you need to sample by a subdivision. I was asked this today and I responded that you need to...

sampling]]>