I think if you showed not only the point estimate, but also some measure of uncertainty like standard deviation, it should have given you a passing grade. It's hard to say why an answer like 6.8 +- 5 is wrong.
Even if you don't yet have formal statistical chops, it should be at least possible to show cumulative distribution function of results that will convey the story better than a single answer with overly optimistic implied precision.
This is early high school. We didn't have error bars yet, we just took an average. I just used that as a convenient way to describe how erratic our numbers were. If 6.8 is the average you know we had some low numbers in there. And some nice high ones, too.
You're certainly correct that the true value would have been in our error bars, and one of those good teachers I acknowledge the existence of in my large paragraph, sarcastic as it may be, could conceivably have had us run such a garbage experiment and shown that as bad as it was, our error bars still did contain the correct value for probably all but one student or something like that. There's some valuable truth in that result too. Cutting edge science is often in some sense equivalently the result of bodging together a lot of results that in 30 year's hindsight will also be recognized as garbage methodology and experiments, not because the cutting edge researchers are bad people but because they were the ones pushing the frontier and building the very tools that later people would use to do those precision experiments with later. I always try to remember the context of early experiments when reading about them decades later.
It would also have been interesting to combine all the data together and see what happened. There's a decent chance that would have been at least reasonably close to the real value despite all the garbage data, which again would have been an interesting and vivid lesson.
This is part of the reason this is something that stuck with me. There were so many better things to do than just fail someone for not lying about having gotten the "correct" result. I'm not emotional about anything done to me over 30 years ago, but I'm annoyed in the here and now that this is still endemic to the field and the educational process, and this is some small effort to help push that along to being fixed.
It's honestly kind of bullshit because the bedrock of a lot of my work is being realistic, and if I had such a piece of crap equipment I would have gladly reported the 6.8 meters per second squared and then turned around and identified all of the problems with my setup right down to characterizing the lag time on the stopwatch start.
In fact one of the trickiest problems I had to resolve once was to show that the reason a piece of equipment couldn't accurately accumulate a volume from a very small flow was because of the fixed-point decimal place they chose. And part of how I did that was by optimizing a measurement device for the compliance of a fixed tube until I got really good, consistent results. Because I knew that those numbers were actually really good it came down to how we were doing math in the computer and then I just had to do an analysis of all of the accumulation and other math to determine what the accumulated error was. It turned out to be in really good agreement with what the device was doing.
All of that came from our initial recognition that the measured quantity was wrong for some reason.
Resale values are lower in US because they factor in the 7.5k USD tax credit and the state tax credit mostly, there is plenty of demand for used teslas for example.
Similar in other countries but sometimes not as direct.
Various regulations set targets which gives manufacturers incentives to hit sales targets. This leads to discounts or great lease deals just before certain dates if targets aren't met through standard prices.
I think it was true, at least in the US, back then the Leaf was the most common EV. Their battery longevity was trash, they had poor range to start with, and tax credits pushed down the effective new price a lot.
The resale values are only low compared to the inflated COVID prices. A 3 year old Tesla 3 goes for about $25k. Which is painful if you paid $70k for the 3. However, the buyer is comparing to a new 3 which you can get for $35k after tax credit.
The opposite will occur when Trump cancels the credit.
This is likely. From example games, it not only knows the rules (which would be impressive by itself, just making the legal moves is not trivial). It also has some planning capabilities (plays combinations of several moves).
The tape delay methaphor confused me. Tape recorders do not record DC or other frequencies much lower than, say, 20 Hz. So that circuit would run into one of the rails just as quickly as the previous cirquit without DC feedback.
It must be an FM encoded tape, which can record DC. There were upgraded versions of both VHS and Betamax with FM audio support (although I expect in practice the inputs were AC coupled).
The above mentioned FM upgrade to VHS, called HI-Fi VHS I believe, had excellent audio recording capabilities. I used it to archive albums back in the day, and when I play some of the warped ones back today, the speaker cone can be seen moving where it would playing the original vinyl.
But not DC itself. Even if it goes down to 1 Hz, the circuit in question will saturate in a few seconds, or be in saturation when initially turned on and never get to zero as there is no DC feedback.
The way I have always come to understand this boils down to what modulation actually is. DC is not modulation. Anything above DC can be, or maybe technically is and must be managed or accounted for. Frequency drift might be one example.
DC is basically continuous wave and the signaling, if any is intended, is basically limited to turning the wave on or off, or the wave just being present.
The VCR was basically reproducing very low frequency waves. One could see the cones moving in and out with the rotation of the 33 RPM vinyl.
The only other analog device that did something similar was an old vacuum tube reel to reel running a very high tape speed. And the effect was not as dramatic.
Both of those devices could basically archive a CD respectably. The VCR added about 3db and the reel a bit more that I was not in a position to measure.
The most striking things about that ancient reel to reel device were that it was rack mounted with some other gear, EQ, pre-amp, amp, and some other things, and how much better it could really do when using pretty great tape at crazy speeds. The highs would start to roll off pretty high, 18khz or so. The usual was 10 to 12.
That was a very fun old piece of gear. Left over relic from the 60's available for curious high schoolers to tinker with.
Who says you have to use an analog PLL decoder? FM audio tape is clearly capable of storing DC because you can store a constant sine wave at a different frequency to your carrier frequency. Maybe you'll decode it with software defined radio software.
Even when you decode with an SDR, you still need to adjust the receiver frequency to match that of the transmitter, as reference oscillators might have slightly different frequencies that can also slowly shift, e.g., due to changes in temperature. In case of a tape recorder, tape speed during recording and playback can also be slightly different due to mechanical factors.
Sync everything to GPS. Record a harmonic of the carrier on the same tape, or just record the carrier itself on a parallel track. Have the SDR use this reference tone to undo any tape speed fluctuation artifacts. You can bring the deviation from DC so low that your comment no longer has any relevance to tape machines and just becomes a pedantic comment that mathematically perfect DC doesn't exist in physical reality.
A metaphor should be referring to something common, not something that can be made in theory to fit a different set of requirements, but does not really exist.
An illustrative example to explain ergodicity. Consider the following game. Players start with $100. At every turn, a fair coin is flipped. If tails, the amount of player's money is increased by 50%. If heads, the amount of player's money is decreased by 40%. To play or not to play, that is the question.
Level IIIA resists penetration from .357 SIG, 9 mm, and .44 magnum. Those are handgun rounds. It may stop some intermediate rounds if you’re lucky, but certainly not full power rifle rounds.
Helmets cannot deform as much as vests before seriously injuring the wearer, limiting their capacity to dissipate kinetic energy. And if you make them too rigid, concussion becomes a problem.
I am not even in Russia, but that war pulled so much out of every region, including mine (which did not see fighting directly, but provided many conscripts and resources), that after the war there simply wasn't much to eat or too many people to work the fields. My grandparents first ate caramel candy in 1952, IIRC. Good luck increasing your fertility rates in these conditions.
Even if you don't yet have formal statistical chops, it should be at least possible to show cumulative distribution function of results that will convey the story better than a single answer with overly optimistic implied precision.