SOMEBODY SUCKS AT BLOGGING

(Hint: it’s me.)

Sorry, people. It’s been a crazy summer. Marriage, job, thesis, all that fun stuff. Plus walking. Lots and lots of walking.

ANYWAY.

The blogs are up*; there are like 150-something of them. Plus a bonus of four earlier blogs that somehow got lost in the ether and never got posted when they were supposed to.

Honestly? You should just unsubscribe. You don’t deserve getting 500 emails saying “Stupid Eigenslacker Lady Just Mass-Posted 5 Months of Drivel, Go Check It Out!”
(I’m assuming that’s how subscriptions work.)

I don’t know how you put up with me.

VROOM!

*Everything should be up except for two of my weekly stats posts. They’re not posted yet because I can’t find the pictures that go with them. For some reason, they’re not will the dozens of other blog pictures I’ve posted over the past few days. Anyway. Once I find the piccys, I’ll post those two blogs, too.

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Protected: List of Things I Miss about Grad School

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How to Read Sheet Music

I keep forgetting to post this, but it’s hilarious. I know at least one person who reads these blogs is a music nerd (MATT!), so you’ll probably like it.

Ask not for whom the Equinox…it nox for thee.

CBC News: reporting the important stuff.

Okay, yeah, those Calgary bathrooms are awesome. Those are the rave ones I blogged about a few weeks ago.

You think Hillary vs. Trump is an important decision? It’s got nothing on Montreal vs. Whitecourt vs. Calgary vs. Calgary vs. Winnepeg!

To be honest, though, any one of those toilets in those bathrooms could run the US better than Trump could.

It’s time for sldfjsl

It’s time for SPACEFEM QUIZZES, ‘cause I ain’t got nothin’ interesting to say today. Sorry.

09-19-2016-a

What color are you?

 

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What color is your rainbow?

 

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Take up a hobby!

 

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The most useless test ever

 

09-19-2016-e

What phase of the moon were you born in?

 

Week 38: The Tetrachoric Correlation Coefficient

Let’s talk about another measure of association today: the tetrachoric correlation coefficient!

When Would You Use It?
The tetrachoric correlation coefficient is a parametric test used to determine, in the population, if the correlation between values on two variables is some value other than zero. More specifically, it is used to determine if there is a significant linear relationship between the two variables.

What Type of Data?
The tetrachoric correlation coefficient requires both variables to be interval or ratio data, but also that both of them have been transformed into dichotomous nominal or ordinal scale variables.

Test Assumptions

  • The sample has been randomly selected from the population it represents.
  • The underlying distributions for both the variables involved is assumed to be continuous and normal.

Test Process
Step 1: Formulate the null and alternative hypotheses. The null hypothesis claims that in the population, the correlation between the scores on variable X and variable Y is equal to zero. The alternative hypothesis claims otherwise (that the correlation is less than, greater than, or simply not equal to zero).

Step 2: Compute the test statistic, a z-value. To do so, the actual correlation coefficient, rtet, must be calculated first. This calculation requires the information on the variables X and Y to be displayed in a table such as the following:

09-18-2016-a

Where “0” and “1” are the coded values of the dichotomous responses for X and Y, and the values a, b, c, and d represent the number of points in the sample that belong to the different combinations of 0 and 1 for the two variables.

Once the table is constructed, rtet is computed as follows:

09-18-2016-b

To compute the z-statistic, the following equation is used:

09-18-2016-c

To obtain h for each variable, first find the z-value that delineates the point on the normal curve for which the proportion of cases corresponding to the smaller of p0 and p1 falls above that point and the larger of the two proportions p0 and p1 falls below. This table lists the ordinates for specific z-scores.

Step 3: Obtain the p-value associated with the calculated z-score. The p-value indicates the probability of observing a correlation as extreme or more extreme than the observed sample correlation, under the assumption that the null hypothesis is true.

Step 4: Determine the conclusion. If the p-value is larger than the prespecified α-level, fail to reject the null hypothesis (that is, retain the claim that the correlation in the population is zero). If the p-value is smaller than the prespecified α-level, reject the null hypothesis in favor of the alternative.

Example
Let’s look at the exam grades for one of the old STAT 213 classes. I want to see if there is a significant correlation between the grades on midterm 1 and midterm 2 as far as whether they got a grade higher than a C+. I will code a grade higher than a C+ as 1 and a grade equal to or lower than a C+ as a 0. Let the X variable be the grade on the first midterm, and the Y variable be the grade on the second midterm. I suspect a negative correlation between X and Y, since a lot of students who did poorly on the first midterm either dropped the class or worked really hard to do well on the second one. Here, n = 105 and let α = 0.05.

H0: ρtet = 0
Ha: ρtet > 0

The following table shows the distribution of the 0’s and 1’s for these two variables:

09-18-2016-d

Computations:
First, let’s find the h values. For midterm 1, p0 = 0.18 and p1 = 0.82. The z-score for which 0.82 of the distribution falls below and 0.21 of the distribution falls above is 0.92. The ordinate, h, of this value is 0.2613 according to the table. For midterm 2, p0 = 0.31 and p1 = 0.69. The z-score for which 0.69 of the distribution falls below and 0.31 of the distribution falls above is 0.5. The ordinate, h, of this value is 0.3521 according to the table. So,

09-18-2016-e

Since our calculated p-value is smaller than our α-level, we reject H0 and conclude that the correlation in the population is significantly greater than zero.

OUCH MY BONES

HAVE SOME ZOO PICTURES ‘cause I keep forgetting to post them.
Well, they’re not “zoo pictures” really. They’re just the butterflies.
BUT THAT TOTALLY COUNTS ‘CAUSE BUTTERFLIES

(I’m hyper.)

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09-17-2016-b

Atlas moths are the best.

09-17-2016-c

Oh, and have a video of these guys. Not sure if this is like a pre-mating thing or if the fluttering one is just having fun annoying the other.

Sorry I don’t have anything more to say today! I spent most of the day doing class prep, which is super fun but time consuming.

The September List?!?!?!

  • Holy hot damn, this has been a good year for music. There hasn’t been an extraordinary number of five-star songs, but there have been a lot of four-star ones that have been extra good. Example, example, example. It’s like 2013 all over again.
  • I found this Klein bottle website like five years ago, but had forgotten about it until randomly finding it again tonight. I totally want those Klein bottle earrings.
  • I found a just-opened Anytime Fitness that’s only a 15-minute walk from campus (as I’ve mentioned before). I’m in the middle of a free 7-day trial there, and I love it. I’m getting back into running, as I mentioned on Saturday, and because nobody knows that the gym is open yet (or even that it’s there), it’s super empty and quiet. I’ve been the only one on the top floor (where all the cardio equipment is) the last few times I’ve been there.
  • Nostalgia! I used to watch this when I was a kid. My mom can confirm.

  • AND THIS:

If I Sits I Fidgets

I saw this animation a while ago, but I just recently found it again. Even just watching it makes me antsy.

I definitely get fidgety and lose my ability to concentrate if I spend too much time sitting. I walk for at least two hours every day (usually it’s closer to three and a half or four), so that’s time spent not sitting, but I still feel like I sit too much. I have no idea how I used to sit so long before I started doing my walks.

Walking helps me concentrate, anyway. If I do my walking in the morning before I go to campus, I feel like I’m a lot more productive, even if I don’t actually start doing any work until 3 or 4 in the afternoon. On the other hand, if I try to work at school first and then go walking, I know I waste a lot more time and just can’t concentrate as well.

Anyway. Now I feel super bad watching this on the day that I didn’t even leave the house, but tomorrow it’s back to walking/running!

Clefairy and Clefable are the best so deal with it

I forgot to mention this yesterday, but THE POKEMON BUDDY SYSTEM IS OUT ASLDFJWEOIFJASDLF

Look at my super cute n’ pudgy Clefable. He’s the best. I’m going to have like 400 Clefairy candies in the next month, watch me.

09-14-2016-a

(You get a candy each time you walk a kilometer with a Clefairy/Clefable.)

I like the sizes of some of the different Pokemon when compared to your avatar.

09-14-2016-b

09-14-2016-c

09-14-2016-d

09-14-2016-e

09-14-2016-f

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Sparkly Beige

It’s TEACHIN’ TIME!

I don’t think I can properly convey my excitement over being able to teach statistics again. I mean, I guess I’ve been running labs for the past two years, but it’s just not the same, you know? I really feel like teaching statistics—especially intro statistics—is what I’m meant to do with my life.

And I know this position is only temporary (I’m technically only hired through December 31st of this year), but I’m going to do whatever I can to see if I can keep it going longer. Surely some of the higher up professors who teach 213/217 would want an opportunity to focus more on their research or on the upper-division courses they’re teaching, right?

Either way, I am eternally grateful to Scott for really pushing those in charge to hire me. I’m pretty sure I would have never gotten this opportunity without his influence. Now I just have to prove that I know what I’m doing and hope that they need somebody for next semester.

Week 37: The Biserial Correlation Coefficient

Today we’re going to talk about yet another measure of association: the biserial correlation coefficient!

When Would You Use It?
The biserial correlation coefficient is a parametric test used to determine, in the population, if the correlation between values on two variables some value other than zero. More specifically, it is used to determine if there is a significant linear relationship between the two variables.

What Type of Data?
The biserial correlation coefficient requires both variables to be interval or ratio data, but one of these variables to have been transformed into a dichotomous nominal or ordinal scale.

Test Assumptions

  • The sample has been randomly selected from the population it represents.
  • The underlying distributions for both the variables involved is assumed to be continuous and normal.

Test Process
Step 1: Formulate the null and alternative hypotheses. The null hypothesis claims that in the population, the correlation between the scores on variable X and variable Y is equal to zero. The alternative hypothesis claims otherwise (that the correlation is less than, greater than, or simply not equal to zero).

Step 2: Compute the test statistic, a z-value. To do so, the actual correlation coefficient, rb, must be calculated first. This calculation is as follows:

09-11-2016-a

The value h represents the ordinate of the point in the standard normal distribution that divides the proportions p0 and p1. To obtain h, first find the z-value that delineates the point on the normal curve for which the proportion of cases corresponding to the smaller of p0 and p1 falls above that point and the larger of the two proportions p0 and p1 falls below. This table lists the ordinates for specific z-scores.

To compute the z-statistic, the following equation is used:

09-04-2016-b

Step 3: Obtain the p-value associated with the calculated z-score. The p-value indicates the probability of observing a correlation as extreme or more extreme than the observed sample correlation, under the assumption that the null hypothesis is true.

Step 4: Determine the conclusion. If the p-value is larger than the prespecified α-level, fail to reject the null hypothesis (that is, retain the claim that the correlation in the population is zero). If the p-value is smaller than the prespecified α-level, reject the null hypothesis in favor of the alternative.

Example

Let’s look at the exam grades for one of the old STAT 213 classes. I want to see if there is a significant correlation between the average grade of students’ two midterm tests and whether or not they got a grade higher than a C+ on the final. I will code a grade higher than a C+ as 1 and a grade equal to or lower than a C+ as a 0. I suspect a positive correlation. Here, n = 107 and let α = 0.05.

H0: ρb = 0
Ha: ρb > 0

Computations:

First, let’s find h. In the sample, p0 = 0.28 and p1 = 0.72. The z-score for which 0.72 of the distribution falls below and 0.28 of the distribution falls above is 0.58. The ordinate, h, of this value is 0.3372 according to the table. So,

09-11-2016-c

Since our calculated p-value is larger than our α-level, we fail to reject H0 and conclude that the correlation in the population is not significantly greater than zero.

I AIN’T NO SQUARE!

Hi.

As I’ve mentioned before (I think?), I recently discovered that there’s an Anytime Fitness like 15 minutes away from campus. Today I got up the courage to go there and ask for the 7-day free trial, ‘cause I want to get back into running BUT the weather’s going to start going to hell soon, so I might as well have a gym as backup for everything, right?

Anyway.

It’s a super tiny little place, but I don’t think anyone knows it’s there (it’s kind of hidden way back in a bunch of buildings) and so there were like four other people there the whole time I was working out.

The equipment seems nice, they have 12 pound weights (10s are too light and 15s are too heavy right now, but it’s super hard to find 12s for some reason), and I spent about an hour on the treadmill running a 10k. I can definitely tell that all my walking has really increased my endurance and my ability to recover after working out. I had no trouble with the 10k itself, and it took less than 15 seconds for my breathing to go back to normal after I finished. My heart rate felt like it went back down to normal pretty quickly, too.

So yeah, even though I’m not doing super hard aerobic exercise by walking, the benefits are still there.

WOO!

*screeching*

MY CLEFAIRY PLUSHIE CAME TODAY AND HOLY HOT HELL ON A STICK IT’S THE CUTEST THING EVER

LOOK AT IT LOOK AT IT LOOK AT IT

09-09-2016

*more screeching*

TWSB: Hey, A Science Blog!

Hey you butt parties, check this out: a study published in the journal Chemical Senses suggests that there may be a sixth taste in addition to the five basic ones we all know (sweet, sour, salty, bitter, umami). What taste is it? Starch.

The study, run by Dr. Juyun Lim from OSU, involved approximately 100 participants across five different studies. The participants were asked to taste liquid solutions of carbohydrates—some simple (like sugar) and some complex—both under normal conditions and when the sweet receptors in their mouths were blocked. Even with the receptors blocked, the participants stated that they could still detect a starchy taste, which goes against previous assumptions that starch was tasteless.

Dr. Lim says that the result is not necessarily surprising; since humans use starch as a major source of energy, it makes sense that humans could be able to detect its presence by taste. If nothing else, the findings demonstrate that the way humans taste is actually more complex than previously thought. The way the participants tasted the starch, says Dr. Lim, was by tasting the saliva-destroyed version of the starch: glucose oligomers. While it was previously suggested that humans could only taste the simple sugars class of carbohydrates, the fact that participants could actually describe the taste of the glucose oligomers suggests that our tasting of carbs is more complicated than we think.

Others are a bit wary of classifying this as a new separate taste, suggesting that it might just be another “version” of the sweet taste. More research will be done on determining the exact mechanism of how the glucose oligomers are actually tasted.

The Mets, The Mets, The Mets are On Fire

Take a look at what the Mets are doing right now:

09-07-2016-a

This is a graph of the Mets’ probability of making it to the postseason. As you can see, the probability had been taking a dive for most of the season, bottoming out at 6.7% on August 19th. They basically had a very, very small chance of making it.

Less than a month later, that probability has shot up to 63%. That’s pretty crazy. They’re just out of the wildcard spot now. I think it’s especially interesting when you consider that none of the other teams even remotely in contention have any huge upswings or downswings (except maybe the Cardinals).

09-07-2016-b

(Sorry, I like graphs.)

(And now I can use the “sports” category for the first time in like 4 years.)

Fidget Cube

The more I look at this, the more I think I want one.

I have a lot of trouble sitting still for any extended length of time. This has gotten worse, I think, as I’ve increased the number of hours per day I spend walking. I don’t like to be sitting still unless I’m really concentrating on something important (or just playing The Sims or something like that). I think having this little cube would help me out, at least partially, when I have to sit for a long time and can’t really move in any other way.

Edit: backed it. I should have a cube in December!

Titles are for Squares

What’s the meaning or inspiration of your blog’s title?
My original title was “Le Seul Mot Juste” because I used to be a pretentious bastard and all pretentious bastards needed a MySpace blog in 2006, right? Now it’s “Eigenblogger,” which I like a lot better. The prefix “eigen” means “own,” so it kind of fits with what I do here, which is basically just blogging for my own sake of archiving my nonsense life. I don’t mind the readers, though!

What do you consider your biggest strength?
Can I say my immune system? My immune system is unstoppable.

What do you consider your biggest weakness?
Everything else.

Tell us why we should like your favorite band.
I don’t know if I have a favorite band. You should like WALK THE MOON because if you ever get the chance to listen to any of their other songs apart from “Shut Up and Dance,” you’ll see that they’re consistently good and not just a one-hit wonder.
You should like Coldplay because Coldplay.

Who is your favorite model of all-time? Why?
Bohr’s model of the atom.
Oh, wait.

Does it bother you when people talk about their pets? Why?
Pets are the best! Why would it ever bother me?

Tell us about your favorite holiday.
LEIBNIZ DAY LEIBNIZ DAY LEIBNIZ DAY LEIBNIZ DAY
Technically it is a holiday up here, but it should be a holiday everywhere, dammit!

What was the last fabulous meal that you ate? Where were you?
Our wedding dinner was pretty fantastic. Fettuccine Alfredo, really tasty sorbet, and our wedding cake had a near-illegal amount of chocolate in it.

What’s your lucky number and why?
I’ve always liked 11. I don’t know if it’s lucky or not, but I seem to run into more than an expected amount of double or triple numbers (like 11 or 66 or 222) in my life.

What are five things you hate?
People who don’t know how to walk courteously, people who don’t know how the crosswalk buttons work, #hashtags, yoga pants in non-yoga situations, emojis. So nothing too serious.

What are five things you love?
Teaching statistics, color, music that makes my crotch tingle, walking, and Nate.

Tell us a secret you can because other than us, who’ll read this anyway?
I just ate like 15 M&Ms. IT’S NOT EVEN M&M TIME YET.

What is the favorite body feature of yourself?
I don’t have one. I hate my body.

Is there a tattoo that you want? If you don’t have one, gun-to-your-head so you have to get one, what would it be?
I’d still like to get a little tiny integral sign tattooed on me somewhere. The main problem is that there’s not really a good spot for a random integral sign without it looking weird.

What do you love about yourself?
“Love…about…self?” I don’t know what these words mean together.

What do you hate about yourself?
I am the worst person. Seriously.

Who is someone you miss?
I miss my dad, yo. It’s not like he’s dead or anything, but I never see him anymore and I miss hanging out with him and my mom together a few times every week. Makes me miss when I was back in Moscow and it was just my mom and my dad and myself and we’d always go out for dinner on Thursdays and he would gossip about the U of I.