Linked Questions

62 votes
6 answers

A chart of daily cases of COVID-19 in a Russian region looks suspiciously level to me - is this so from the statistics viewpoint?

Below is a daily chart of newly-detected COVID infections in Krasnodar Krai, a region of Russia, from April 29 to May 19. The population of the region is 5.5 million people. I read about it and ...
CopperKettle's user avatar
  • 1,213
55 votes
4 answers

How do we decide when a small sample is statistically significant or not?

Sorry if the title isn't clear, I'm not a statistician, and am not sure how to phrase this. I was looking at the global coronavirus statistics on worldometers, and sorted the table by cases per ...
Avrohom Yisroel's user avatar
34 votes
6 answers

Line graph has too many lines, is there a better solution?

I'm trying to graph the number of actions by users (in this case, "likes") over time. So I have "Number of actions" as my y-axis, my x-axis is time (weeks), and each line represents one user. My ...
regulatethis's user avatar
24 votes
5 answers

What could be the reason for using square root transformation on data?

What is the primary reason that someone would apply the square root transformation to their data? I always observe that doing this always increases the $R^2$. However, this is probably just due to ...
MarkDollar's user avatar
  • 5,985
10 votes
3 answers

Choosing c such that log(x + c) would remove skew from the population

I have data for which I would like to take the log transformation before doing OLS. The data include zeros. Thus, I want to do a log(x + c). I know a traditional c to choose is 1. I am wondering ...
user1690130's user avatar
8 votes
2 answers

Log vs square root link for Poisson data in R

I am currently working to model deaths from AIDS over time using a GLM in R. I know that there are two possible options for the link function for Poisson data, log and square root. I know that square ...
Ellie's user avatar
  • 81
14 votes
2 answers

Is visualization sufficient rationale for transforming data?

Problem I would like to plot the variance explained by each of 30 parameters, for example as a barplot with a different bar for each parameter, and variance on the y axis: However, the variances are ...
David LeBauer's user avatar
3 votes
1 answer

Understanding variance stabilization and its uses

I recently came across the variance stabilization method that tries to remove the dependency of variance from the mean (for example consider Poisson distribution). ...
RTM's user avatar
  • 191
3 votes
2 answers

Model approach for count data with a large range of y values

I am modeling ridership data for specific routes by month over a number of years. Some routes have as little as about 1000 riders per month while other routes may have over 20,000 riders per month. ...
CooperBuckeye05's user avatar
1 vote
1 answer

log transforming a Poisson variable

Trying to understand how log-transforming a count variable changes the regression equation. The reason I ask is because I see a lot of researchers log-transform their data so they can use OLS. Say you ...
invictus's user avatar
  • 523
7 votes
1 answer

What is the specific issue with using count data for ANOVA tests

I'm running a study with a between-groups component and a within-groups component, with a predictor that is count data. I was planning on using split-plot ANOVA to analyze this, but after seeing lots ...
cjfcjf's user avatar
  • 439
5 votes
1 answer

When is it appropriate to apply a transformation?

I understand Box-Cox transformations, when to apply which transform (log vs exponential) and on what type of distribution (left vs right skewed). However, what I don't understand is when is it ...
Josh Muroe's user avatar
4 votes
2 answers

Closest approximation of a Poisson GLM using weighted least squares analysis to take into account mean/variance relationship

I have an application where I would like to approximate a Poisson GLM with identity link, i.e. a glm of the form ...
Tom Wenseleers's user avatar
3 votes
1 answer

General Linear Model Univariate with unequal variances - what are my options?

I'm using SPSS to run a GLM (general linear model) univariate with 1 fixed factor (Treatment) and one random factor (experimental replicate). There are 4 treatment groups. The measurement is number of ...
Rebecca's user avatar
  • 41
7 votes
2 answers

Population model to model year to year dynamics

My task is to assess how various environmental variables affect annual population fluctuations. For this, I would use a model like: $$ \mbox{log} ( \mu_{i,j+1} ) = \mbox{log} ( \mu_{i,j} ) + R_{j} + \...
Tomas's user avatar
  • 6,211

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