Linked Questions

62 votes
6 answers
8k views

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
8k views

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
26k views

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
62k views

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
4k views

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
5k views

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
525 views

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
6k views

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
3k views

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
2k views

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
865 views

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
1k views

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
2k views

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
2k views

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
1k views

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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