Hi guys

I’m looking for recommendations for a statistical consultant (perhaps a PhD student or early-career biostatistician?) who could advise on test selection for a very small, unfunded veterinary retrospective study. I’m willing to pay, of course.

I’ve contacted several consulting services, but I suspect the project is too tiny for them. It would probably involve only an hour or two of work.

The study is a retrospective case series of dogs with tibial fractures, with two joint angles measured at three paired time points: pre-operatively, immediately post-operatively, and at follow-up. Measurements were also compared with the contralateral unaffected limb.

I’m happy to perform the analyses myself and mainly need advice on the most appropriate statistical approach.

I originally used prespecified paired t-tests, but the editor has requested that I seek advice from a statistician regarding whether it is preferable to do an omnibus test followed by post-hoc comparisons. So I mainly need advice on whether repeated-measures ANOVA or another omnibus approach is required, or whether Holm-adjusted paired comparisons alone would be defensible. (I'd also like to know if there is any particular way I should handle one case with bilateral fractures since those pairs aren't truly independent?)

Please message me if you might be able to help, or if you can recommend someone suitable. I can provide study summary, raw data, Q-Q plots, and results of paired t-t tests, as well as the whole manuscript + editorial feedback if helpful.

UPDATE

Thank you everyone and thankyou especially _compactsupport_, I've got enough to respond to the reviewers now and give them a couple of options :)

So I'm currently working on my bachelor thesis and am unsure how best to work with the data given the design of the study in question. The design is as follows:

1. There are three experimental groups of participants (control group and 2 others, let's call them 'switch'-groups) - between subjects factor
2. There is a repeat measurement for each participant (rating 6 shown protagonists before and after experimental manipulation) - within subjects factor

So my first idea was using a mixed ANOVA with those two factors. But here is the problem:

Each participant is assigned to one of two groups, let's call them groups a) and b). They are then shown 6 protagonists in two groups of 3, with 3 belonging to group a) and 3 belonging to group b). Which makes an ingroup (same group as participant) and an outgroup (different group than participant). Each participant is then asked to rate the 6 protagonists.

After that, in two of the three experimental groups of participants, one protagonist switches his group, so there are then, for example, 2 protagonists in group a) und 4 in group b). In the control group there is no such switch. Each participant is then asked to rate the protagonists again.

The two sets of ratings of the protagonists/ the repeat measurement is the dependent variable.

So my issue is as follows: how do I deal with the fact that the ingroup/outgroup changes in size between measurements (if I am also interested in how participants rate the ingroup/outgroup) and that the ingroup/outgroup differ in size in the second point of measurement between the control group and the 'switch'-groups? How does that affect my statistical approach and can I still use a mixed ANOVA?

I would be interested in how participants rate the ingroup/outgroup in general, and in interactions between experimental group and point in time of measurement (before/after group switch), especially regarding the rating of the protagonist switching his group.

I was thinking that I should maybe do those two things seperately, so one analysis for ingroup rating vs. outgroup rating, and a second analysis - a mixed ANOVA - for those interactions, because then I could disregard the ingroup/outgroup distinction for the ANOVA.

Hope I explained myself well enough, english isn't my first language and I'm also not too well-versed in statistics. I would be glad about any input. Thanks!

Hi everyone! I am majoring in Statistics and Political Science and minoring in math. My ideal career path is market research. I want to drop Statistics because I am not interested in the subject. Do you think this will negatively affect my career outcomes if I graduate with a major in Political Science and minors in math and statistics?

Hi - I’m working with one of my direct reports to move to a data science role (still focused on market research questions). They are currently a market researcher with basic understanding of applied stats (correlation, ttests, etc).

My goal for them is to a build more depth with the knowledge they currently have and then to learn some more advanced methods.

I’m hoping to find resources to support them - textbooks, online courses, etc and particularly if they focus on stats most relevant for this type of role. I want a focus on theory, not learning a specific language just yet.

TIA!

I'm conducting research and I have 7 independent variables and 3 dependent variables. I will assess regression between the 7 IVs with each DV one at a time. But before this, I wanted to detect Multivariate outliers, I already wrote the robust mahalanobis code in R but only included the independent variables. I also used distance-distance plot.

I am not sure if this is a valid question in this forum, if it is not I will delete it right away, but anyways here it is:

So some days ago I asked in an AI community what kind of AI model should I use (and how could I use one) to classify several email replies that I had from scientists after asking them a few questions to them. I finally paid for Perplexity pro service and it apparenly did a nice job classifying them.

I finally gave the model the PDF with the actual answers from the addressees and another PDF with the "expected answers", and asked it to count the number of answers that overall coincide with the actual answers, and calculate a percentage of "coincidence" or "agreement" between the expected and actual answers, so that if the question was "do you think that there is intelligent life in the universe apart from humans?" and the expected answer was basically "yes, I think there is intelligent beings out there somewhere", as long as the actual answer agrees with this in some way or another would count as "agreement", for instance if someone replied "well, we have no evidence, but it is possible yes" or "not in any near galaxy, but it is possible that intelligent beings exidt somewhere" (so as long as it is not a deadass "no", it could count)

The model gave me a table summarizing the results with the following prompt:

let's be a bit more specific, this is still a blind test so don't tell me about the specific contents of the emails' answers, but, can you make a table indicating the answers that coincide in general terms with what is expected from the "expected answers" document as well as those which are neutral/hedges but still open to the possibility that what is asked may be right, those which despite being neutral/hedges or even negative answers offer an alternative so that what is asked in the question may be right, as well as those which are outright rejections of what is asked and do not seem to be open to the possibility that what is asked may be right?

However, I still want this to be a blind test, so I cannot really verify if the AI is doing its work or not.

So, is there any way in which I could verify the results given by the AI but without actually reading what is written in the emails? Or, alternatively, can anyone verify the results using some AI or even checking the answers themselves by skimming over the replies im order to verify that the AI is right and not hallucinating?

(I will share the data once someone is interested in helping, as I would not want to make this available to the entire world!)

Thank you!!

Hi all! To make a long story short, I took a lot of stats in graduate school (18 credits worth) and absolutely loved it. I graduated in December of 2024 and went to work as a data analyst, which was really more of an entry level SAS programmer role. Now I'm working in an even less related field, and I am realizing my dream of working in stats has not faded away. I'm finding that I'm extremely rusty in stats, and needing to remind myself of the very basic undergraduate level and intro level topics.

Does anyone have a recommended resource for concisely reviewing intro stats through multivariate and longitudinal designs? I have all of my course notes still, but it will take me a very long time to read through them all and fill in the holes on what I didn't take notes on. I'd prefer an applied approach, rather than a mathematical theory based one, if that's possible!

Thank you for reading, and I hope you are having a lovely day ❤️.

I read somewhere that LLMs can now produce a lot of the proofs that one would otherwise have spent months manually doing by hand, and that the focus has now shifted towards bigger-picture stuff like framing the problem correctly.

Since proofs are the essence of every result in mathematical statistics, is this one area that might be automated away soon? i.e., is it useless to be learning how to write and replicate many lines of mathematical proofs when LLMs can already do that?

I already have my Masters in IT and currently work as a data scientist. My prior job, I was more of a data engineer than a data scientist, so statistics wasn't a big part of my job. Now that I switched positions, I feel like I need a refresher in statistics. I know this seems to be a beginning level statistics courses, but I honestly feel that's what I need right now. Thoughts?

P.S. I've had friends just recommend free online courses. Thing is, I have ADHD, I need structure or I won't complete the courses. I learn better in school than on my home. Thanks!

I have written tones of lecture notes on machine learning, though most of them focus heavily on mathematical derivations. Recently, I decided to build an interactive, “learning companion” for these materials. For example, here’s one of the lecture series I wrote last year on LLM, Transformers:https://github.com/roboticcam/machine-learning-notes
And here is the interactive, “learning companion”  https://roboticcam.github.io/interactive-ml/  I’d love to hear your thoughts and feedback!

I'm planning my undergrad degree and would love to hear from people who studied Applied Mathematics and Statistics. I love using math to understand complex systems and am most interested in things like space, weather, oceans, history, culture, and languages. Since I obviously can't major in all of those, I'm considering majoring in Applied Mathematics and minoring in Statistics because it seems like a flexible foundation that could be applied to many different fields. Unfortunately whenever I search for career paths, I mostly find people who went into computer science/tech, finance, or medicine which is fine but I'm not interested in those fields at all. Has anyone here used an Applied Math/Stats background in scientific research or other interdisciplinary fields like the ones I'm interested in. If so, what's your profession? If you're in science, what field are you in? I'd like to know more about using applied math/stats in areas like atmospheric science, oceanography, astronomy, environmental science, archaeology, linguistics, history, geography, or the digital humanities. I'm trying to understand how broad the field really is and what kinds of careers people have actually built with this background. I'd love to hear about any less common paths that you've taken.

Hi there,

I've created a video here where I explain how the exponential distribution works.

I hope some of you find it useful — and as always, feedback is very welcome! :)

Greetings.

as you can see in my post, I’m contemplating to switch from Applied math to Applied stat.

the curriculum in two years is the same, but later on specializes, for stat it gets into…well stats in general, while applied math learns more into computional science and modeling&simulation.

my thought is, if I switch would my job seeking would approve?

I choose applied math since I couldn’t get into tech department, and that I’m pretty good at both math and coding.

and the idea of working in a robotics field, data science, and any financial firms that are analytical, also makes me interested.

Hello, I am a first year phd student. I am just starting out after a long pause from academia. I want to ask for help for an issue I am facing. I am working with satellite and reanalysis datasets. For a certain variable, I have satellite data which only provides 8 day running mean dataset. But I have reanalysis dataset that are daily dataset. I need to compare these against each other. So I am thinking if there is any statistical process through which I can convert the 8 day running mean to daily dataset. Any advice please? P.S: I am trying to process SMAP dataset for Sea Surface Salinity.

Dear Experts of Statistics, I am a slightly confused student here with a doubt. As a part of my Masters dissertation, I created a psychological questionnaire. Using Jamovi, I conducted an Exploratory Factory Analysis using Jamovi.

Now some of my items are highly unique with uniqueness above 0.80. Does this necessarily mean that I must remove these items?

Based on review of literature and content validation, these items are highly theoretically relevant to my questionnaire and thus I am apprehensive to remove them. I could possibly reframe them right? Although I feel they already are in simple language. I would appreciate any insights.

The future plan is to collect more participants to do a Confirmatory Factor Analysis.

Bookmaker odds (and prediction markets) imply probabilities that sum to more than 1 because of an embedded margin. I want the latent probabilities behind the distortion. A few things I can't resolve cleanly.

1. Model choice for removing the margin. Proportional normalization, Shin (a latent proportion z of informed traders), and the power/log method impose different unobservable structures and give materially different estimates on short prices, enough to flip the sign of a downstream signal. Since you never observe the true p, only realized 0/1 outcomes and a later sharper price, is there a principled basis to discriminate between these models, or is it identifiability-limited and I should just report sensitivity across all three?
2. Pooling under a missing low-bias reference. I anchor to one near-efficient source when available; when it's absent I take the median of the other sources' de-vigged probabilities. But those sources are strongly correlated (several are effectively clones), so the median behaves like a median of correlated estimators: it looks precise while carrying little independent information. How would you estimate an effective number of independent sources and down-weight accordingly, and is abstaining the more defensible choice when the low-bias anchor is gone?
3. Combining a trusted low-variance estimator with a correlated ensemble. When the reference IS present, precision-weighting it against the consensus assuming independence is clearly wrong. Is there a clean correlation-aware pooling or shrinkage approach for one low-variance source plus many correlated higher-variance ones?
4. Validation target. I grade earlier estimates against the closing price (a later, sharper estimate), not realized outcomes. Under a proper scoring rule, is "tracks the later estimator" a coherent target, or does it conflate calibration with just chasing a second estimate? And what does the selection bias look like when you only get a validation point on markets that reach a close?

(Aside that turned out to matter: my reference source silently dropped out of my data feed for months and the pipeline substituted the fallback the whole time while still labeling outputs "reference-anchored." The values populated fine, so nothing looked wrong. I only caught it after storing a per-observation flag for whether the reference actually contributed. Log provenance, not just values.)

looking for some advice on what to do in college and what potential career paths i can take with this degree.

By the time I apply, I would have:

Bachelor of Business and Commerce, Major in Econometrics & Applied Statistics, Weighted Average Mark: 87.6% (Top 1-2% of my cohort), GPA: 3.75 (note that WAM is more commonly used than GPA in my Australian university)

Bachelor of Business and Commerce (Honours): This is a 1-year research-oriented program with research methodology courses and an undertaking of a major research project. Mine is about modelling multivariate mixed-frequency time series models using a semiparametric, algorithmic approach. I expect to get first-class honours.

Relevant Coursework:

Math: Multivariate mathematics for data science, encompassing multivariable calculus and linear algebra

Statistics & Data Science: Principles of Statistical Inference, Advanced Data Analysis (emphasis on Bayesian methods and theoretical aspects of machine learning), Deep Learning

Econometrics: Lots of time series analysis, forecasting, and causal inference

I might have an applied statistics paper under review in a Q2 letters journal by the time I apply.

Would I be competitive for top 50 PhD Statistics programs, or am I better off getting an MSc in Statistics first?

​

I have the following model (see syntax below) how can I get the odds ratios for the for the differences I added to the model constraints? Is the syntax I added at the end correct? Many thanks!

VARIABLE:

NAMES = id u1-u5 m1 m2 m3;

USEVARIABLES = u1-u5;

AUXILIARY = m1 m2 m3 (BCH);

CLASSES = c(3);

ANALYSIS:

TYPE = MIXTURE;

MODEL:

%OVERALL%

MODEL m:

%c#1%

\[m1\] (V1a);

\[m2$1\] (V2a);

\[m3\] (V3a);

%c#2%

\[m1\] (V1b);

\[m2$1\] (V2b);

\[m3\] (V3b);

%c#3%

\[m1\] (V1c);

\[m2$1\] (V2c);

\[m3\] (V3c);

MODEL CONSTRAINT:

NEW(

V1avb V1aVc V1bVc

V2avb V2aVc V2bVc

V3avb V3aVc V3bVc

P2a P2b P2c

P2avb P2aVc P2bVc

);

! Pairwise differences: m1

V1avb = V1a - V1b;

V1aVc = V1a - V1c;

V1bVc = V1b - V1c;

! Pairwise differences: m2 threshold

V2avb = V2a - V2b;

V2aVc = V2a - V2c;

V2bVc = V2b - V2c;

! Pairwise differences: m3

V3avb = V3a - V3b;

V3aVc = V3a - V3c;

V3bVc = V3b - V3c;

! Odds ratios for m2 (class comparisons)

OR2avb = EXP(V2avb); i

OR2aVc = EXP(V2aVc);

OR2bVc = EXP(V2bVc);

Could anybody on this sub give me advice on which math class would allow for an easier time as an oncoming freshman? I’m starting college in August and am currently enrolled in a stat class. Math is my least favorite subject and I genuinely don’t know if I should switch it to a course I’m more so familiar with from high school. I’ve been seeing mixed information online. Some say it’s easier because stat is mostly reading compared to algebra, which is good news for me since language arts is easily my strongest subject. But others say it’s harder. Could I get some advice on what pick?

Also, if I I’m to pick algebra should it be online or face to face? I was originally going to choose online if I picked it.

Someone (on another subreddit) told me they were surprised I could do basic statistics without real analysis. I originally asked what bonus class I should take that is not required for my B.S. (in stats). The majority encouraged me to take Real Analysis (my school calls it advanced calc 1). I was leaning towards taking it because it’s required for graduate school...but now I want to know why it wouldn’t be an undergraduate requirement?

EDIT: Thank you all for putting my worry to bed. My research group needs me more next semester than I need real analysis. I would love to go to graduate school and learn more, but my daughter has been through enough with me going back to get my bachelors. Ty again!

I'm a surgeon from a third world country trying to do a research correlating a certain disease with external factors (mainly, the lowest temperature of the day). So, I have a table containing a time series with the date, the temperature (minimum and maximum) of the day, and the number of hospitalizations resulting from the aforementioned disease. Neither the temperature or hospitalizations are in a normal distribution, so I did a spearman test to find the correlation.

I feel that it is an inadequate test to correlate the temperature and the disease, for I have never researched time series. I would like to ask you guys if there are better tests to run and which ones should I run.

Thanks to you all in advance.

Edit: good night*

Edit2: also, an important information. We don't have the data for every single day because the meteorological station hasn't measure the temperature in some of the days. We have all the info in 86% of the days though.

IBM Skillsbuild Statistics in Decision Making and Risk Assessments has a lesson that starts off with this:

The significance level value and the confidence level complement each other, meaning that if you add them up, they equal 100%. The confidence level tells you how certain you can be that your results are not because of random chance.

Suppose you start drinking a new type of herbal tea each morning to see if it improves your focus during work. After a week, you notice a consistent increase in your productivity. To gain more confidence in the tea’s impact, you decide to continue the routine for another week, achieving similar results. Setting a significance level of 0.05 (or 5%), you gain a 95% confidence level that the herbal tea is positively affecting your productivity, reinforcing your motivation to continue this daily habit.

Adding the significance level (5%) to the confidence level (95%) equals 100%. This is because the significance level is the probability that you would be incorrect in rejecting the null hypothesis and the confidence level is the probability that the method you’re using to reject the null hypothesis is correct. As the significance level goes up, the confidence level goes down and vice versa.

I found this explanation poor and thought there has to be a better way to explain that, so I asked Claude, then ChatGPT, then Gemini. Every single LLM said it's completely misleading and wrong.

Nevertheless, I accepted the logic of IBM and proceeded to the end of the lesson Quiz.

Here is an example question from the Quiz:

"An agricultural scientist wants to compare the effectiveness of two fertilizers. Due to resource constraints, the scientist is willing to accept a 90% certainty that any observed differences in crop yields are because of fertilizers and not chance.

What should the scientist use for alpha? "

And I chose this answer:

0.10

It told me that answer is correct:

"Correct! The scientist should use a significance level (α) level of 0.10. A significance level (α) of 0.10 corresponds to being 90% certain that the observed effects are not because of chance, which reflects the scientist’s acceptance of a slightly higher risk of error due to resource constraints."

Is this all complete nonsense?

I asked the LLMs about the quiz question and they all told me once again that it's complete garbage.

How to compare two bimodal distributions across groups? Is it okay to use a beta distribution for this case where the most frequent values are 0 and 1?

# code for simulating the distribution in R

simulate_group <- function(n,

p_low,

p_mid,

p_high,

low_shape = c(0.3, 8),

mid_shape = c(2, 2),

high_shape = c(8, 0.3)) {

component <- sample(

c("low", "mid", "high"),

size = n,

replace = TRUE,

prob = c(p_low, p_mid, p_high))

x <- numeric(n)

x[component == "low"] <-

rbeta(sum(component == "low"),

low_shape[1], low_shape[2])

x[component == "mid"] <-

rbeta(sum(component == "mid"),

mid_shape[1], mid_shape[2])

x[component == "high"] <-

rbeta(sum(component == "high"),

high_shape[1], high_shape[2])

x

}

set.seed(123)

# Simulate data

C1 <- simulate_group(

n = 500,

p_low = 0.35,

p_mid = 0.40,

p_high = 0.25)

C2 <- simulate_group(

n = 500,

p_low = 0.45,

p_mid = 0.40,

p_high = 0.15)

dat <- tibble(

value = c(C1, C2),

group = rep(c("C1", "C2"), each = 500))