Posts tagged ‘Math Jokes 4 Mathy Folks’
Today, I asked my son’s if they would like to buy The Oatmeal’s Why Grizzly Bears Should Wear Underpants. They laughed uproariously at the title, and then Eli asked, “Is that the #1 book on Amazon?” In fact, it’s not. At the time of this writing, its ranking was #624. “That’s not #1,” Alex affirmed, then added, “but it’s a lot better than your book.”
“A lot better” is highly subjective. Sure enough, the #3,517 ranking of Math Jokes 4 Mathy Folks has an absolute difference of 2,893 compared to WGBSWU; or, if you’re into ratios, the rank of my book is five times as much as the rank of WGBSWU. But what does that really mean?
In practical terms, it means that the number of copies of WGBSWU that will sell on Amazon this week is approximately six times the number of copies of MJ4MF that will sell during the same period. If my calculations are correct, that is. No one is really sure how ranking translates to sales, but I estimate that approximately 250 copies of MJ4MF and 1,500 copies of WGBSWU will sell this week.
This is what math geeks do: We try to understand everything quantitatively.
I took weekly sales data for MJ4MF and compared that with the book’s average ranking for the week. I randomly chose 20 weeks in 2012-13 for this analysis, because while pulling weekly sales data is relatively easy — it’s provided at Amazon Author Central — determining weekly average ranking is more difficult, since data has to be pulled day by day. And it’s not as simple as just exporting the data to Excel or a CSV file… the data is provided in a graph, and if you want to manipulate that data in any way, you have to look at each point on the graph, determine its value, and then enter it manually. Ugh.
The graph below shows the relationship between average rank and weekly sales:
The regression equation S = 914.77 × R-0.977 gives a reasonably good fit (r = 0.89). What’s interesting is that this formula is less accurate in November and December than during the rest of year. There are two reasons for that. First, sales increase dramatically during the holiday shopping season. Second, such a formula is bound to be less accurate with larger numbers.
The average rank for December 9-15 was #3,592, and using the formula above, approximately 253 copies of MJ4MF should have sold. (I suspect that estimate is a little low. For the same week last year, the average rank was #4,573 and 277 copies were sold.)
Amazon posts sales data for each week on the following Friday. Sales data for last week won’t post until December 20. I’ll update this post on Friday and let you know how well I did.
[Update, 12/20/13: A record-breaking 335 copies of MJ4MF sold December 9-15. (Thank you!) But as predicted, the estimate was indeed low. As I gather more data, perhaps I will be able to create a better model.]
Through some special features at Amazon Author Central, I am able to know the daily sales rank of Math Jokes 4 Mathy Folks. My sales rank at the end of each of the last three days was 44,404, 96,990, and 35,355, respectively. I thought that was interesting — three days in a row when the sales rank was a five-digit number in which one digit occurred at least three times. What’s the likelihood of that? Stated more formally:
Assuming that the sales rank of MJ4MF is always a five-digit number, what is the probability that three consecutive days’ sales ranks will contain a digit that occurs in the sales rank at least three times?
The sales rank of MJ4MF has never been a five-digit number in which the same digit is repeated five times. (Bummer!) The probability of that occurrence, though, is even less likely than the situation described above — though I won’t tell you exactly how much less likely, so as not to spoil your fun!
Here’s a math problem for today:
The sum of three consecutive integers is 27. What is the product of the integers?
Today is August 9, 2010, also known as 8/9/10. It’s no coincidence that today was chosen as the official publication date for Math Jokes 4 Math Folks.
You can preview the first chapter on the NCTM web site.
You can also order a copy online at the following online retailers.
Thanks to those of you who purchased a pre-publication copy. To those of you who buy a copy in the future — thanks in advance!
Will you or someone you know be in Colorado Springs this weekend? So will I! I’m doing a book signing at Borders Southgate. Details below.
Booksigning at Southgate Borders – Math Jokes 4 Mathy Folks
Why is 6 afraid of 7? How many mathematicians does it take to screw in a light bulb? What type of lingerie does a mermaid wear to math class? Learn the answer to these and other questions at Borders Southgate on Saturday, June 26, when author Patrick Vennebush will talk about his book, Math Jokes 4 Mathy Folks.
Borders Books, Music, Movies & Cafe
2120 Southgate Road
Colorado Springs, CO 80906
Saturday, June 26
Are you aware that April is Math Awareness Month?
And did you know that April is also National Humor Month?
Those two things mean that:
- This is a great time for me to present the Math Joke Hour at the 2010 NCTM Annual Meeting in San Diego, April 21‑24. The Math Joke Hour will be held Wednesday, April 21, at 2:30pm in Room 6E of the San Diego Convention Center. Hope to see you there!
- It’s an even better time to buy Math Jokes 4 Mathy Folks! You can purchase it directly from Robert D. Reed Publishers; or, if you’re attending the NCTM Annual Meeting in San Diego, you can pick up a copy in the bookstore at a 25% discount.