November 5, 2017 at 8:53 PM by Dr. Drang
Last week Apple released its 2017 Q4 (which everyone else’s calendar says is 2017 Q3) sales and revenue figures, which means a boatload of graphs from all your fave rave Apple-oriented bloggers. I’m a few days late, as usual, despite having long ago written scripts to generate these graphs.
I don’t make as many graphs as everyone else, partly because I’m lazy, but mainly because don’t care about revenue. My concern is the popularity of the devices I use, not how expensive they are. I want third-party developers to keep writing apps for them, and that means there has to be a market for them out there.
Here’s the summary graph, with the sales figures for the three main Apple products. The dots are the quarterly sales and the lines are the four-quarter moving averages.
The iPhone dominates the scale of this graphs, so it’s helpful to also see the iPad and Mac on their own graphs.
The good news is the second straight quarter of year-over-year increase in iPad sales after its long, well-documented slide since 2013. Additional good news is the Mac’s slow but consistent rise over the past year—four straight quarters of year-over-year sales increases. Imagine how much better the figures would be if people really liked the Touch Bar.
I think its fair to say, though, that the iPhone 7 was something of a dud. It had a good start, but its non-intro quarters had almost exactly the same sales as the 6S had. Look at the final three quarters of each.
As I’ve argued before, the iPhone 6S sales looked lackluster only in comparison to the gangbusters popularity of the iPhone 6. If one ignored the year of the 6, the 6S’s sales were more or less on the same upward trend as the previous three editions. The iPhone 7 was on that same trend for its first quarter but went dead flat after that.
Apple’s report in January will be very interesting.
November 2, 2017 at 9:02 PM by Dr. Drang
Do you use Keyboard Maestro (or AppleScript or whatever) for one-time, throwaway macros as often as you should? I know I don’t, but I did put one together a couple of days ago and used a feature I’d never tried before.
I had one of those recalcitrant PDFs that I often get from clients. This one was 25–30 pages long, each an E-sized floor plan drawing for a building. The drawings were all black-and-white, but the PDF had color annotations added. I needed to add my own annotations to most of the pages, but something about the format of the file made it very cumbersome to work with. I tried Preview, PDF Expert, and PDfpen Pro, and they all were glacially slow when panning, zooming, and switching pages.
So I broke the file up into individual pages using PDFtk:
pdftk drawings.pdf burst
The single-page files didn’t make me wait for the spinning beach ball, so I was able to add my annotations quickly in PDF Expert. Then came an impasse.
I wanted to email the drawings with my annotations back to the client and to some other parties, but they were too big to fit in an email. I could use multiple emails, but that’s a recipe for losing some of the files. I could use a Dropbox link, but I had a sense that one of the other parties wouldn’t understand how that worked. What seemed best was to convert the files to JPEGs at the lowest legible resolution, zip them together, and send the zipped file in a single email.1
My normal practice would be to use
sips for this, because I can issue a single command to convert any number of files. But I soon learned that
sips doesn’t handle annotations properly when converting the format of a file from PDF to JPEG. In my brief testing, I found that neither my annotations or the ones that came from the client were visible in the converted JPEGs.
Preview, though, can export a PDF as a JPEG with the annotations intact and visible. Which presumably means that
sips and Preview are using different code bases for the conversion. Whatever.
The problem with using Preview is I’d have to convert every file by hand. Not the most burdensome job I’ve ever had, but one that’s boring and susceptible to error. Enter Keyboard Maestro.
Here’s the macro that exports the current file in Preview to a JPEG and closes it:
You’ll note there’s no step for setting the resolution for the exported file. That’s because once it’s set, it doesn’t change from one export to the next.
I didn’t try to have the macro open each PDF in turn, because I didn’t trust myself to do that right. I just opened all of them and then ran the macro by pressing ⌃⌥⌘J repeatedly. The macro closed each file after exporting it, leaving the next window ready to be operated on.
The new (for me) thing with this macro was the “and drag to” part at the bottom of the third step. That’s what moved the popup menu selection fromup to .
I figured out how much to drag by taking a screenshot like the one above and using a selection in Acorn to measure the vertical distance from the center of to the center of . No trial and error.
With 25–30 files to convert, it’s possible I did save time with this macro. But the main reason I made it was to avoid the tedium and the likelihood of error on my part. These are not independent—I’m far more prone to make errors when the task is repetitive and doesn’t maintain my attention.
No, a Dropbox link is really no more complicated than a zip file, but zip files are more familiar to more people. And although zipping JPEGs doesn’t make them smaller, it does package them up in a way that naive Windows users are usually comfortable with. It would be lovely if I always worked with people whose computer skills were trustworthy, but that’s not the world I live in. ↩︎
October 30, 2017 at 1:14 PM by Dr. Drang
While reading a recap of last night’s World Series games, I saw this statistic: of the 65 Series that have had a sixth game, the team with the 3–2 lead has won the Series 43 times. This was, I think, intended to show us that the Astros have a strong chance to beat out the Dodgers for the title. And they do. But not as strong as you might expect.
If the teams were evenly balanced and each game independent of the others, we would expect the team with the 3–2 lead to win 75% of the time. 50% of the time they’d win the sixth game and the Series would be over; 25% of the time (50% of the other 50%) they’d win in the seventh game. So the leading team “should” have won the Series 48 or 49 times out of 65, not 43 times.
Is this 5 or 6 game difference meaningful? For that we need to do some calculations using the binomial distribution. Python’s SciPy set of libraries has a subsection of statistical modules, including one for binomial distribution calculations. We can import it this way:
python: from scipy.stats import binom
Let’s start by figuring out the probability that the leading team would win 43 times in 65 trials. With a 75% probability of winning the Series in each trial, the probability of 43 Series wins in 65 chances is calculated through
python: binom.pmf(43, 65, .75)
pmf function gets its name from the standard abbreviation for “probability mass function.” The answer is 0.029 or just under 3%. This makes it seem very unlikely that our assumption of 50–50 games would lead to only 43 Series wins for the leading team.
But that isn’t the way these sorts of calculations are normally done. If we want to find out if a seemingly out-of-whack result is “statistically significant,” we should look at the probability of results that are at least as far away from our expectations as the actual result was. In our case, that means looking not only at the probability of 43 Series wins out of 65 chances, but also 42 wins, 41 wins, and so on. We then add up all of these “at least as weird” probabilities.
The usual terminology for this sort of summation is “cumulative distribution function,” and the
binom module has a function for it:
python: binom.cdf(43, 65, .75)
The result is 0.0695, or about 7%. Another way of looking at this is that if our assumption of 50–50 games were correct, there’s a 93% chance that the leading team would win the Series more than 43 times in 65 chances.
In hypothesis testing, the value 0.0695 is called the p-value, and it’s common in many fields to consider a result statistically significant if its p-value is less than 0.05. Using that criterion, we would not take the difference between our “null hypothesis” of 50–50 games and the World Series history as statistically significant.1
But it’s something for Dodgers fans to cling to.
Yes, I’ve been a little breezy here with my definition of null and alternate hypotheses and one-sided vs. two-sided rejection areas, but it’s just baseball. ↩︎
October 28, 2017 at 9:33 AM by Dr. Drang
I can’t say I wasn’t warned. The concert’s promotional artwork (especially those fonts) and the previous two albums, Shadows in the Night and Fallen Angels, were strong clues that I was going to be seeing a Bob Dylan infected by the Great American Songbook.
So yes, we got “Melancholy Mood” and “Autumn Leaves” and “The September of My Years” with Bob crooning into a big microphone and holding its stand at a jaunty angle. But that’s not what I disliked about the concert. In fact, those songs were done pretty well, and Dylan’s voice sounded better than any previous concert I’ve been to. It was what he did to his own songs that was frustrating.
No one in his right mind goes to a Dylan concert expecting to hear his classics played or sung the way they were done originally. But the treatment they’re given is always interesting and usually fun. Not this time. Apart from “It Ain’t Me, Babe” and “Highway 61 Revisited,” the Dylan songs suffered from arrangements that were, I guess, meant to match the style of the non-Dylan songs. Under these conditions, you can’t expect the songs to rock, but you can expect them to swing. And the band just didn’t swing.
There was a sameness to Charlie Sexton’s guitar work throughout the night. Despite changing instruments several times, his sound was constrained and repetitive. But when a band doesn’t swing, it’s mainly because of the rhythm section. These are talented musicians who can play in any style, so if they didn’t find a groove it must have been because Bob didn’t want them to.
As a result, he lost the audience. Many left early and those who hung in there stayed glued to their seats until the encores. Can you imagine a Dylan audience not standing to “Tangled Up in Blue”?
The optimist in me notes that Dylan never sticks with anything for long, and after two albums of standards he may be ready for the next thing. I hope he comes back to the notion that that it’s his songs, and the blues and country/folk they came out of, that are truly the Great American Songbook and gives them the treatment they deserve.