shout-out to calca

A man makes a smug expression, lifts his eyebrows, and nods

On my last homework, I started using Calca rather than a vanilla calculator. It’s nice to have the calculation history through a problem; I mean, most scientific calculators don’t have a “tape” you can look back on easily.

This morning I learned that Calca knows the quadratic formula, which is nice when I’m dealing with ugly equations I need to find the roots of.


nerd thoughts

In tonight’s lecture on time series analysis, my brain keeps seeing capital-phi

Capital letter Phi from the Greek alphabet

and interpreting it as the Deathly Hallows symbol.

The Deathly Hallows symbol: an equilateral triangle, with a circle inscribed, and a vertical line from the top to the bottom.

That’s all. Nothing earth-shaking tonight, just nerd thoughts.

Linear regression models

I’m studying linear regression (and time series analysis) this term, so naturally the graphics will feature these topics. As always, these are licensed via Creative Commons for non-commercial use.

6 steps to a linear regression model
1. Identify outliers
2. Find multicollinearity
3. Find and assess models
4. Assess predictive power of the models
5. Analyze residuals
6. Write the report
Creative Commons License

6 steps to a linear regression model by Heather Rollins is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

statistics is beautiful #6

Last semester, in my Statistical Modeling class, we studied a whole pile of hypothesis tests and confidence intervals.  After a few, I realized that they all took a very similar form.  The note-taking sheet below (PDF download here) lays out blocks for left-tailed test, right-tailed test, two-tailed test, and the confidence interval, with spaces to fill in the parts of the  hypothesis test as described in an earlier stats is beautiful post.

As always, this page is Creative Commons licensed, asking for attribution to Heather Rollins or to this blog’s URL for non-commercial use.  For commercial use, send me an email first. Thank you, and enjoy!


statistics is/are beautiful #5

I can’t really lay claim to this one. A student in my Design & Analysis of Experiments class gave this answer tonight. I’ll have to ask my professor who it was, so that appropriate credit can be given.  🙂


Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

gearing up for the holidays at work

‘Twas two days before Christmas, when all thro’ Web Teks
Not a worker was working, not Tom and not Zack;
vacation requests had been duly considered
in hopes that somebody would do something billable;

the workers were tapping away at their desks,
while daydreams of holidays danced in their heads;
and Sarah in her Ugg boots and John in his sweater,
wishing their employees would do something better;

when in the cafe there arose such a clatter,
I sprang from my desk to see what was the matter.
Away to the glass door I flew like a flash,
To see several pans falling down with a crash;

the sun shining brightly this Chesapeake morn–
bet you thought I would rhyme that line with the word ‘pr0n’–
illumined the car of our great boss Dyanne,
its trunk open, showing lots of food and some pans;

And there she stood, Dyanne, her hands on her hips,
“Could you help me?” she asked, and I jumped to assist;
More rapid than eagles she tossed me her tools,
and she named ev’ry one as to my arms it flew:

“Now, Toaster! now, Hot Plate! now, OJ and Cups!
On, Pancake Mix! Butter! on, Bread! Knife that cuts!
To our cafe please take them, and carry them well,
Then send out the guys to give me a spell.”

All laden we carried in food and supplies
equipping Dyanne to cook before our eyes;
so into the cafe went her griddles and meats,
to make us a holiday breakfast replete

with omelettes to order–cheese, ham, peppers, too–
fresh pancakes, hot bacon, and toast made just so.
As I went to my desk and I sat down to write,
Dyanne started to mix a meal sure to delight.

She was dressed in her apron from ECPI,
and her smile was clear on her face and her eyes.
a whisk for the eggs she held loose in her hand,
a spatula near to flip cakes in the pan.

Then she called out our names: “Karim! Charles! and Jeff! too,
come down and get breakfast: I’ve finished your food!”
As co-workers arrived, they joined in on the fun,
and placing their orders, each and every one,

The omelettes were awesome, the pancakes divine,
and the bacon and sausage were  certainly fine;
with syrup, toast, butter we garnished our plates,
then we sat down for breakfast: we ate and we ate!

After all had completed and eaten our fill,
we thanked our kind boss, praising her chef-ing skill.
And we heard her exclaim, as she cleaned up from brunch:
Happy Christmas to all! In two hours, it’s lunch!”