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Book quiz data geekery, plus another free book

The winner of the Numbersense Book Quiz has been announced. See here.

GOOD NEWS: McGraw-Hill is sponsoring another quiz. Same format. Another chance to win a signed book. Click here to go directly to the quiz.


Numbersense_quiz1_timingI did a little digging around the quiz data. The first thing I'd like to know is when people sent in responses.

This is shown on the right. Not surprisingly, Monday and Tuesday were the most popular days, combining for 70 percent of all entries. The contest was announced on Monday so this is to be expected.

There was a slight bump on Friday, the last day of the contest.

I'm at a loss to explain the few stray entries on Saturday. This is very typical of real-world data; strange things just happen. In the software, I set the stop date to be Saturday, 12:00 AM, and I was advised that they abide by Pacific Standard Time. This doesn't seem to be the case, unless... the database itself is configured to a different time standard!

The last entry was around 7 am on Saturday. Pacific Time is about 8 hours behind Greenwich Mean Time, which is also the ISO 8601 standard used by a lot of web servers.

That's my best guess. I can't spend any more time on this investigation.


The next question that bugs me is how could only about 80% of the entries contained 3 correct answers. The quiz was designed to pose as low a barrier as possible, and I know based on interactions on the blog that the IQ of my readers is well above average.

I start with a hypothesis. Perhaps the odds of winning the book is rather low (even though it's much higher than any lottery), and some people are just not willing to invest the time to answer 3 questions, and they randomly guessed. What would the data say?

Numbersense_quiz_durationeligiblesHaha, these people are caught red-handed. The boxplots (on the left) show the time spent completing the quiz.

Those who have one or more wrong answers are labelled "eligible = 0" and those who have all 3 answers are labelled "eligible = 1".

There is very strong evidence that those who have wrong answers spent significantly less time doing the quiz. In fact, 50 percent of these people sent in their response less than 1 minute after starting the quiz! (In a boxplot, the white line inside the box indicates the median.)

Also, almost everyone who have one or more wrong answers spent less time filling out the quiz than the 25th-percentile person who have three correct answers.

As with any data analysis, one must be careful drawing conclusions. While I think these readers are unwilling to invest the time, perhaps just checking off the answers at random, there are other reasons for not having three correct answers. Abandonment is one, maybe those readers were distracted in the middle of the quiz. Maybe the system went down in the middle of the process (I'm not saying this happened, it's just a possibility.)


Finally, among those who got at least one answer wrong, were they more likely to enter the quiz at the start of the week or at the end?

Numbersense_quiz1_eligiblebyday There is weak evidence that those who failed to answer all 3 questions correctly were more likely to enter the contest on Friday (last day of the quiz) while those who entered on Wednesday or Thursday (the lowest response days of the week) were more likely to have 3 correct answers. It makes sense that those readers were more serious about wanting the book.


Now, hope you have better luck in round 2 of the Numbersense book quiz. Enter the quiz here.





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