Distribution type

I didn’t know where to turn with this problem, so I hope someone in here can help me. ​ So i got a data set the amount of time it takes to pass precisely 3 check points. My sample is n=30, where n represents the time it takes to pass all 3 check points. My problem is interpreting the distribution type. My Chi-square test indicates that is normally distributed, however I have this gut-feeling that it has somewhat of a Poisson distribution to it. My reasoning behind this, is that each check point would have an average amount of passing time. With that reasoning, I could state the probability of a certain amount of check points passed within a given time frame, giving a value to lambda. So my question is, am I correct in this reasoning? Note that the average passing time is about 300[sec]. My book (“Applied statistics and probability for engineers, sixth edition” by Douglas C. Montgomery and George C. Runger ) indicates that if lambda is greater than 5, the data can be normally approximated for a Poisson distribution (p125). What’s your opinion on this problem? Thanks in advance! submitted by /u/IWF_weightilifting [link] [comments]

Building a simple HMM model for my PI—need reference suggestions

I’m a college student Cell Biology, but I’ve been wanting to get into bioinformatics for graduate school. I’m comfortable coding, but I feel like I haven’t really connected the amount of math/statistics I need to really get where I want to be. I’m close to graduating and likely can’t take additional classes, but would anyone have a good source so I could look at how people implement probability theory into their algorithms? I need to both do some review after a few years away from statistics and math as well as get a better understanding of how it can provide more sound architecture for programming. submitted by /u/Jeru1226 [link] [comments]

What are the disadvantages of the Mann-Whitney u-test?

In my daily job, I like to use Mann-Whitney u-test instead of Student’s t-test when I need to compare the mean of the two distributions. Therefore I don’t need to bother with assumptions about the normality of my data. So I was wondering what are disadvantages of the U-test and why we need t-test for that, when seems like u-test is a much more flexible solution? submitted by /u/alexander-osipenko [link] [comments]

Hessian Matrix not sigular in Poisson/negative binomial regression

Hey all, I’m in the middle of running a whole heap of Poisson and negative binomial regressions via SPSS. Everything was going smoothly until about my 8th regression I encounters this issue: “The hessian matrix is not singular. Some convergence criteria are not satisfied” ​ What I’m confused about is each regression is using the same IV but each with a different DV. If the hessian matrix is calculated using the IV’s how come some models work and others are getting this error? ​ Additionally, what steps would I need to take to fix the error? ​ Thanks! submitted by /u/lgleather [link] [comments]

Moment/Probability Generating Functions – Struggling to understand

Hi all, ​ I was wondering if anyone has any good resources that helped them to understand moment and probability generating functions? I believe it might be a weak point in my maths (have not studied power or generating functions ) rather than statistical understanding. I’ve tried going through the often recommended textbooks (Wasserman, Casella, Wackerly etc) and it just doesn’t seem to click for me. Can anyone help me out? Was anyone in a similar position and found a particularly useful resource? ​ Thanks Sef submitted by /u/Sef_ [link] [comments]

Simple Questions – October 19, 2018

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. submitted by /u/AutoModerator [link] [comments]

How do you sample from a distribution?

I’ve literally never understood the concept of sampling. So first off, does “a sample” mean literally one point sample, or is it a collective noun for a set of points all “sampled” independently? Also, how do you do this “sampling”? Say I have the standard Normal distribution, and maybe a Bernoulli distribution. How would I sample from these? I think I might understand it better if I actually code these (which I want to do on my own), so I’d like an intuitive explanation. submitted by /u/FlyingQuokka [link] [comments]