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Visualizaiton workshop at UBC B.I.G. Research Day. 11 May 2016

# Alex — Internet's Most Popular Rat

## Poster Rat for Rat Genome Sequencing

The rat genome sequencing project at the Baylor College of Medicine Human Genome Sequencing Centre is complete. The genome has been analyzed and published.

I'd like to introduce you one of the faces of the project: Alex, the genomics rat idol.

Arguably, Alex is the most popular rat on the internet. For the justification of this strong statement, read on.

Alex, the rat. Rattus norvegicus on an ABI 3700 genome sequencer. (zoom)
Alex, the rat. Rattus norvegicus on an ABI 3700 genome sequencer. (zoom)

## Alex's Biography

Alex was born in May 2000. It's well known that a rat's cuteness reaches maximum at about 3-4 weeks. After this critical time, a pet store rat is less likely to be purchased and may be asked to act as snake food. In Alex's case, she was perilously close to her deadline. Luckily for her, we paid a ransom of \$6.99 to the Noah's Ark pet shop in Vancouver. She was on her last cute leg.

Portrait of Alex, the genome rat (Rattus norvegicus). Here, she is seen in a forced portrait position (zoom)

From May 2000 Alex spent most of her time hoarding food pellets and riding on shoulders.

Portrait of Alex, the genome rat (Rattus norvegicus). Riding on shoulder.

Alex liked to bite. And rats only bite hard — they don't nibble. Her contention for this unattractive behaviour was the uncanny similarity between a finger and a pellet of food.

Other than unpredictable bouts of biting (by far the most exciting aspect of her personality), Alex lacked other distinguishing characteristics.

Alex died of a seizure in late 2002. She was buried outside of the Museum of Anthropology. A ratty pair of underwear served as a burial shroud.

And I hope you got that last pun.

Photos are for public use. Use, modification and distribution of these photos is unrestricted.

## Alex's Popularity

Despite my best efforts at meaningful work, this web page continues to be the most popular of all my online offerings, making for a somewhat embarrassing achievement.

Alex's images consistently show up first in Google's web search for 'rat', 'rat image' and image search for 'rat'.

Alex image is the first for Google's 'rat' search query (retrieved 16 Mar 2013). (rat Google search)
Alex image is the first for Google's 'rat image' search query (retrieved 16 Mar 2013). (rat Google search)

Finally, Alex appears as the first entry in Google images for 'rat'.

Alex image is the first for Google's 'rat image' search query (retrieved 16 Mar 2013). (rat Google search)

## Alex's Public Appearances

Alex is neither without modesty nor public fame. Her first cover-ratgirl appearance was on the April 2004 issue of Genome Research.

Alex the rat appeared on the cover of Genome Research (April 2004). (zoom)

More recently, she's appeared on the cover of Ethnologie Francaise (Jan-Mar 2009 issue).

Alex the rat appeared on the cover of Ethnologie Francaise (1/2009). (zoom)

The topic of the issue was the relationship between animals and humans. It is fitting therefore to recount here the relationship I shared with Alex during her sojourn with us.

VIEW ALL

# Regression diagnostics

Wed 11-05-2016

Residual plots can be used to validate assumptions about the regression model.

Continuing with our series on regression, we look at how you can identify issues in your regression model.

The difference between the observed value and the model's predicted value is the residual, $r = y_i - \hat{y}_i$, a very useful quantity to identify the effects of outliers and trends in the data that might suggest your model is inadequate.

Nature Methods Points of Significance column: Regression diagnostics? (read)

We also discuss normal probability plots (or Q-Q plots) and show how these can be used to check that the residuals are normally distributed, which is one of the assumptions of regression (constant variance being another).

Altman, N. & Krzywinski, M. (2016) Points of Significance: Analyzing outliers: Influential or nuisance? Nature Methods 13:281-282.

Altman, N. & Krzywinski, M. (2015) Points of Significance: Multiple Linear Regression Nature Methods 12:1103-1104.

Altman, N. & Krzywinski, M. (2015) Points of significance: Simple Linear Regression Nature Methods 12:999-1000.

# Analyzing Outliers: Influential or Nuisance?

Fri 08-04-2016

Some outliers influence the regression fit more than others.

This month our column addresses the effect that outliers have on linear regression.

You may be surprised, but not all outliers have the same influence on the fit (e.g. regression slope) or inference (e.g. confidence or prediction intervals). Outliers with large leverage—points that are far from the sample average—can have a very large effect. On the other hand, if the outlier is close to the sample average, it may not influence the regression slope at all.

Nature Methods Points of Significance column: Analyzing Outliers: Influential or Nuisance? (read)

Quantities such as Cook's distance and the so-called hat matrix, which defines leverage, are useful in assessing the effect of outliers.

Altman, N. & Krzywinski, M. (2015) Points of Significance: Multiple Linear Regression Nature Methods 12:1103-1104.

Altman, N. & Krzywinski, M. (2015) Points of significance: Simple Linear Regression Nature Methods 12:999-1000.

# Typographical posters of bird songs

Mon 28-03-2016

Chirp, chirp, chirp but much better looking.

The song of the Northern Flicker, Black-capped Chickadee, Olive-sided Flycatcher and Red-eyed Vireo. Sweet to the eye and ear. (details)

If you like these, check out my other typographical art posters.