In statistics, when you test hypotheses, you can make two kinds of mistakes.
But those mistakes are based on your null hypothesis. What’s that? Students and practitioners are often very confused about this. They think the null hypothesis has to have some deep significance to the data they’re looking at. Not so (although it might be useful if it did). What is most important about the null hypothesis is that you can describe how the data is going to behave if it is true. You don’t need to know if the null is true or not to be able to do that, and in fact you may never know if it really is true.
In the images, the null hypothesis is that you’re not pregnant. We never know (before the test, and sometimes even after) whether that’s true or not. But if it were true, the data would behave in a certain way: mustaches might be observed, or maybe presenting a swollen abdomen would not be observed, and a host of other more important details that might show up in urine or blood.
A Type I error is what you get when a true null hypothesis is rejected in favor of the alternative. Again, you never know for sure, but it’s plausible that if you’re null is that someone isn’t pregnant, and they have mustaches, and you conclude that they’re pregnant, you’ve probably made a mistake.
A Type II error is what you get when a false null hypothesis is not rejected. Again, you never know for sure, but it’s plausible that if you’re null is that someone isn’t pregnant, and they present with a swollen abdomen, and you conclude that they’re not pregnant, you’ve probably made a mistake.
I always thought I was not a fan of disco (and I’m probably not). But back in 1998, when MP3s were new, and Napster didn’t yet exist (remember MP3Wolf and other programs), this was one of the first 100 or so songs I downloaded. At the time, I was only looking for things I didn’t own, and that you didn’t hear on the radio any more … one hit wonder sort of things.
Truth be told, that was also the time when the stores were filled with follow-ups to Big Mouth Billy Bass, and I’m pretty sure I heard “Rock the Boat” from a lobster in a drugstore that summer, for the first time in 20 years.
Disclaimer: I can be a bit of a conservation scold, so I have no problem with the intention of the literature … just with its stupidity.
Anyway, this was an 8 page flyer passed out to elementary school students. It’s written for kids, but I wonder if it was written by kids as well.
My biggest complaint is with this stunner:
First it tells you to total up your number of bulbs by type. Good, so far.
If I can go so far as to use spreadsheet labeling, you’ve just filled in A1 and A2, and summed them to get A3=A1+A2.
Then it tells you to multiply those totals by the annual cost of electricity per bulb. Still good. You now have your total cost of electricity for all bulbs of each type in your house.
Continuing the spreadsheet theme, you’ve just made D1=A1*C1 (and D2=A2*C2).
Lastly, it tells you to multiply the entries in column D by the total number of bulbs (line 3). Make no mistake about it: that’s a direction to multiply by A3. This means that you’ll have E1=(A1+A2)*A1*C1 (and something similar for E2).
Yes, you’re reading that correctly: they’re telling kids that the way to measure the cost of energy is to square the number of light bulbs they have.
BTW: Column B is pointless if they’re going to direct you to use Column C.
The rest is small beer … but it sure is fun.
Efficiency just must not be selling as a buzz word these days:
Why call it wattsmart if you’re already calling it efficient? And, if it’s such a big deal to call it wattsmart … wouldn’t you title the section that way? I mean … they titled the whole booklet with it:
I’d think this already puts wattsmart above energy efficiency in the pecking order. Perhaps putting both italics and bold typefaces into one word just addled the author’s brain.
This appears alongside a graphic showing windmills, solar cells, and dams:
Yes, we make a big stink about our renewable sources of energy, and then tell the kids that we don’t use anything renewable to make electricity. Perhaps this is a Freudian slip (if I can project that behavior onto a firm).
I do sort of get the point of this one: that we turn primary/natural resources into a secondary/useful resource:
But having said that, is it OK to call electricity a resource? And, if, say coal and the electricity from coal are both resources, aren’t you double-counting?
Here’s how to keep the heat out:
Most middle-schoolers know that once the infared radiation gets inside the window, it’s in for good. The blinds just keep it … on the other side of the blinds.
I don’t even know where to start with this one:
Hmmm. Using both crude and unrefined is repetitive. How is petroleum different from oil (again, remember the target audience)? Isn’t refined oil already a petroleum product? Is there any such thing as refined oil? Isn’t the whole point that most of it isn’t oil any more … thus the different names?
Now, I know we could quibble about this one:
But … do you know of any nuclear plants that don’t use uranium? Yes, they can use plutonium … but why not say that? Plus, to me the wording suggests that some nuclear plants might just be using coal. I wouldn’t be surprised if they have a subsidy scheme in Europe that can make that a viable alternative.
This is really a disaster:
Hydropower is not “energy from water”. It’s the conversion of the potential energy of water at one altitude into kinetic energy by letting it drop to a lower altitude. In short, it’s capturing gravity with water.
From the department of redundancy department:
Read that one again: “Wind is energy from the wind”. Yes, it really does say that.
Now perhaps I’m a little nitpicky we these, but it seems to me if you’re going to give a bullet list under a heading, the first item shouldn’t be repeating or defining the heading:
I didn’t selectively edit those: reuse and recycle have one suggestion, but reduce only has an alternative definition.
Here’s how to save water (I can see that the power company might want me to save hot water, but not just any water):
That’s right! The glass is half-full with less water, and half-empty with more air.
You’re gonna’ love this one. They recommend you use CFL’s instead of incandescent bulbs. Fair enough … but we all know about the disposal issues, and they’ve go that covered:
Go ahead, click this link http://www.getenergysmart.org. It redirects an interested junior CFL recycler in the intermountain west to this New York State government site … with 355 words … not one of which is either CFL or disposal. If you put in “CFL disposal” into its search bar, you do get 3 links on the same site, and if you click through again … you get a map of places to safely dispose your CFL’s in New York. I’ll make sure to have the vXgirl bring any dead CFL’s I have in Utah when I visit Buffalo. Oh … one thing … where do I found out if it’s safe to bring a CFL in her Hello Kitty luggage?
And omigosh … it gets so much better. It shows a map of New York, and a text box where you can enter your zip code. And if you enter one that’s not in New York … it crashes!
And you gotta’ love the ending:
That’s right kids! If you fill out the survey about how to save energy, we’ll give you a nightlight to save less of it!
N.B. I wrote this a year ago, and am posting it now that my daughter is out of that grade and school.
Nation’s Math Teachers Introduce 27 New Trig Functions
All Graduating Students Must Master Gamsin, Negtan, Cosvnx, 24 Others
The vXboy is 14 now, and decent at math. A couple of weeks ago he asked me to explain triangulation. I started with “Have they taught you sine and cosine?” He’d never heard of them. I’m not sure he understands triangulation, distance estimation, depth perception, or any of the related topics.
As part of the same discussion, I asked him if he knew how to use a compass to determine a baseline. Nada.
FWIW: Several years ago I was told that my state’s math curriculum eliminated the topic of commutativity. You know, that 3 times 4 is the same as 4 times 3. This has repeatedly created problems for college students in my classes (in fact, a marketing professor down the hall felt that one of our “brighter” students actually became abusive because he was so certain that commutativity did not hold – that student later got an MBA from us).
… For even a mild bout of pondering the emergence of intelligence is going to conclude that it is genetically based. And if it is then some people are going to end up with a healthier dollop of it than others. And it will obviously also be inheritable.
However, this isn’t politically acceptable to a certain section of the commentariat. I’ve seen, for example, in Danny Dorling’s writings a flat out statement that all babies are equal and that any differences are entirely due to nurture and environment. Anyone could, in his phrase, grow up to be a Professor of Social Geography at Sheffield.
A statement so barking [mad] as to make one conclude that anyone has. For we can clearly see that genes exist for unintelligence: how else are we to explain Down’s Syndrome? … [emphasis added]
You have to read the whole passage to get the context of what I emphasized.
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