Simple Questions – July 12, 2019

This recurring thread will be for questions that might not warrant their own thread. We would like to see more conceptual-based questions posted in this thread, rather than “what is the answer to this problem?”. For example, here are some kinds of questions that we’d like to see in this thread: Can someone explain the concept of maпifolds to me? What are the applications of Represeпtation Theory? What’s a good starter book for Numerical Aпalysis? What can I do to prepare for college/grad school/getting a job? Including a brief description of your mathematical background and the context for your question can help others give you an appropriate answer. For example consider which subject your question is related to, or the things you already know or have tried. submitted by /u/AutoModerator [link] [comments]

Simple Questions – July 05, 2019

This recurring thread will be for questions that might not warrant their own thread. We would like to see more conceptual-based questions posted in this thread, rather than “what is the answer to this problem?”. For example, here are some kinds of questions that we’d like to see in this thread: Can someone explain the concept of maпifolds to me? What are the applications of Represeпtation Theory? What’s a good starter book for Numerical Aпalysis? What can I do to prepare for college/grad school/getting a job? Including a brief description of your mathematical background and the context for your question can help others give you an appropriate answer. For example consider which subject your question is related to, or the things you already know or have tried. submitted by /u/AutoModerator [link] [comments]

Simple Questions – June 28, 2019

This recurring thread will be for questions that might not warrant their own thread. We would like to see more conceptual-based questions posted in this thread, rather than “what is the answer to this problem?”. For example, here are some kinds of questions that we’d like to see in this thread: Can someone explain the concept of maпifolds to me? What are the applications of Represeпtation Theory? What’s a good starter book for Numerical Aпalysis? What can I do to prepare for college/grad school/getting a job? Including a brief description of your mathematical background and the context for your question can help others give you an appropriate answer. For example consider which subject your question is related to, or the things you already know or have tried. submitted by /u/AutoModerator [link] [comments]

Weekly /r/Statistics Discussion – What problems, research, or projects have you been working on? – June 26, 2019

Please use this thread to discuss whatever problems, projects, or research you have been working on lately. The purpose of this sticky is to help community members gain perspective and exposure to different domains and facets of Statistics that others are interested in. Hopefully, both seasoned veterans and newcomers will be able to walk away from these discussions satisfied, and intrigued to learn more. It’s difficult to lay ground rules around a discussion like this, so I ask you all to remember Reddit’s sitewide rules and the rules of our community. We are an inclusive community and will not tolerate derogatory comments towards other user’s sex, race, gender, politics, character, etc. Keep it professional. Downvote posts that contribute nothing or detract from the conversation. Do not downvote on the mere fact you disagree with the person. Use the report button liberally if you feel it needs moderator attention. Homework questions are (generally) not appropriate! That being said, I think at this point we can often discern between someone genuinely curious and making efforts to understand an exercise problem and a lazy student. We don’t want this thread filling up with a ton of homework questions, so please exhaust other avenues before posting here. I would suggest looking to /r/homeworkhelp, /r/AskStatistics, or CrossValidated first before posting here. Surveys and shameless self-promotion are not allowed! Consider this your only warning. Violating this rule may result in temporary or permanent ban. I look forward to reading and participating in these discussions and building a more active community! Please feel free to message me if you have any feedback, concerns, or complaints. Regards, /u/keepitsalty submitted by /u/AutoModerator [link] [comments]

Are there any metrics that approximate the order of a markov process?

I’m working with Approximate Entropy for my thesis. It basically is a way to approximate the difference in conditional distributions of a markov process at different segments in time. The idea is that the larger the change in distributions, the more complex a system (random time series’ distribution wont change that much, neither would a simple time series). I feel like this metric doesn’t work well across different time scales. Now there are other variants of this metric that try to handle this, but I’m curious if the underlying distribution is even remotely relevant. If the goal is to measure complexity, wouldn’t knowing the order of the markov process be the best metric? If your process depends on something that happened 100 steps ago, then it’s more complex and naturally lead to a bigger change in probability distributions between step 99 and 100 (compared to one that just depends on one step). It would also account for all time scales, because the steps can occur at any time interval. submitted by /u/pretysmitty [link] [comments]

Doing a 4-way mixed ANOVA with 40 combinations of variables and trying to test normality. Normality is violated for 26/40 combinations, and log transforming doesn’t seem to work. What do I do?

Hello all, hoping someone can help me out here. I’ve got 3 within-group factors and 1 between-group factor. It is a 2x3x4x5 ANOVA, so excluding the between group factor, I’ve got 40 separate combinations of within-group variables. I performed Levene’s test for normality and it showed that normality was violated for 26/40 variables. I attempted to log transform a couple of them, but the log transformation just made them worse with regard to normality. ​ The thing is that the dependent variable is accuracy, and has a maximum score of 12. So as some variables are far easier than others, some variables will have most people scoring an 11 or 12. I’m very rusty with stats and this is my MSc, and I have no idea what to do. In what case can I just proceed with the ANOVA? Do I have to do a nonparametric test? ​ Thanks heaps. submitted by /u/gumbaline [link] [comments]

Data Science/Statistics and Marketing

Hello all: Please forgive me if this type of post is not allowed or has already been answered somewhere. I am currently acting as a Director of Marketing for a medium-sized business. Most of my work revolves around digital marketing strategy and execution. As I examine the business landscape, it’s become apparent that statistics and analysis are becoming more and more prevalent when making marketing decisions. Next spring, my company is paying for me to complete the Graduate Certificate in Marketing Management & Digital Strategy at Harvard. I was checking out their website and noticed that they had some free Data Science courses. If you don’t mind, I have a few questions for the community: My impression is that data science can integrate with marketing. Am I correct here, or should I be looking for something different? It seems that the free courses at Harvard are through edX. Assuming the answer to the above question is “yes”, will this program give me the knowledge I seek? I took a few calculus and statistics courses during my MBA tenure, but it’s been a few years. Should I refresh my abilities or will this be covered in the material? Thank you in advance! submitted by /u/AlexanderTox [link] [comments]

Should I choose a regression model

Hello everyone, I would like to start by apologizing for asking such a basic question, but when it comes to choosing statistical models I’m overwhelmed by all the options. (My background is medical, not scientific) Basically, my research question is: do my markers show a stepwise increase concordant with the stages of a staging model. The staging model is of course categorical, patients are scored 0 – 4 based on disease severity. The clinical markers are categorical or continuous, for example age at onset, familial loading, blood-derived markers. I think a regression model will do? Any websites where I can learn more about statistical models? submitted by /u/new_in_R [link] [comments]

Bayesian analyis made easy(ier)

I’m going to be estimating the effect of an intervention for a client and we’re woefully underpowered for the question at hand. As is company policy in such situations, we’d rather hand the client statements about a posterior distribution (there’s a 50% chance this impact was positive) instead of a statistical signficance findings (p-value>0.05). In this situation the structure of our data are complicated, so the likelihood P(y|theta_0), where theta_0 is the treatment effect, is complicated. A colleage is suggesting an easy way out: first find impact estimate theta_0 using standard methods, then find estimated treatment effects theta_1, theta_2,…, theta_j from reasonably similar interventions, then form the likelihood using these estimates as the data, as in theta_j~normal(mu,sigma). We would then state a prior on the theta_j, mu, and sigma, and viola: posterior distrubtion of theta_0. This almost seems like cheating to me. Is it valid? It’s so much easier then using our data for the likelihood. It’s more of a hierarchical bayes method. Any thoughts would be appreciated. submitted by /u/foogeeman [link] [comments]